if_rk_dwc: Disable setting delays for now

The values for tx/rx delays differs accross the different DTS.
Mainline Linux set it to 0x24/0x18
Mostly-Vendor u-boot (the one maintained and developped) to 0x18/0x18
Mostly-Vendor linux (the one maintained and developped) to 0x26/0x11

By experience only 0x18/0x18 works so until the issue is resolved rely on
the bootloader settings.