MFC r348169-r348170, r348172-r348173, r348183-r348184

r348169:
Define macros making it easier to define bus-specific pnpinfo for FDT systems.

Pnpinfo is bus-specific and requires the bus name. The FDTCOMPAT_PNP_INFO()
macro makes it easier to define new FDT-based pnpinfo for busses other than
simplebus.

Differential Revision: https://reviews.freebsd.org/D20382

r348170:
Add pnpinfo for icee(4) on fdt systems.

r348172:
Use the new FDTCOMPAT_PNP_INFO() macro to define SPIBUS_FDT_PNP_INFO().
Also rename SPIBUS_PNP_INFO -> SPIBUS_FDT_PNP_INFO because there could be
other kinds of pnpinfo for other (non-fdt) bus attachments.

r348173:
Rename IICBUS_FDT_PNPINFO -> IICBUS_FDT_PNP_INFO because all the other
existing pnpinfo-related macros right now use PNP_INFO, not PNPINFO.

r348183:
Add pnpinfo.

r348184:
Add pnpinfo to all i2c drivers that have FDT compat data.