Fix vnic fallback PHY name matching after r334880.

[markj]

Summary

In some cases it seems that the PHY mode can only be identified by
matching against the corresponding device node name in the FDT. r334880
broke this for the case where the node name contains a unit address.
Fix the problem by allowing a match in that case.

Test Plan

vnic attaches. The relevant portions of the FDT look like this:

                                bgx0 {

                                        #address-cells = <0x1>;
                                        #size-cells = <0x0>;
                                        reg = <0x8000 0x0 0x0 0x0 0x0>;
                                        xfi@0 {

                                                reg = <0x0>;
                                                local-mac-address = [fc 15 b4 97 48 b7];                                                                     
                                                phy-handle = <0x75>;
                                        };
                                        xfi@1 {

                                                reg = <0x1>;
                                                local-mac-address = [fc 15 b4 97 48 b8];                                                                     
                                                phy-handle = <0x76>;
                                        };
                                };
...
                                        mdio@87e005003800 {                                                                                                   
                                                                                                                                                              
                                                compatible = "cavium,thunder-8890-mdio";                                                                      
                                                #address-cells = <0x1>;                                                                                       
                                                #size-cells = <0x0>;
                                                reg = <0x87e0 0x5003800 0x0 0x30>;                                                                           
                                                xfi@0 {

                                                        reg = <0x0>;                                                                                         
                                                        compatible = "cortina,cs4223-slice";                                                                 
                                                        linux,phandle = <0x75>;
                                                        phandle = <0x75>;
                                                };
                                                xfi@1 {

                                                        reg = <0x1>;
                                                        compatible = "cortina,cs4223-slice";                                                                 
                                                        linux,phandle = <0x76>;
                                                        phandle = <0x76>;
                                                };
                                        };

[sbruno]

Let me do a quick test on the cluster ThunderX1 machine.

[sbruno]

This works for us in the FreeBSD cluster. Thanks!