So far bsd.stand.mk wasn't included in the following files:
sys/boot/fdt/Makefile
sys/boot/uboot/fdt/Makefile
sys/boot/uboot/lib/Makefile

This causes compilation issues on MIPS due to trying to link PIC with non-PIC
code. This revision includes bsd.stand.mk in the above files.

Reviewed by: imp
Approved by: adrian (mentor)
Sponsored by: Smartcom - Bulgaria AD
Differential Revision: https://reviews.freebsd.org/D5311