drivers/intel/fsp2_0: Include stddef.h in soc_binding.h
soc_binding.h includes FSP headers which define NULL macro. Because of
this, including stddef.h after soc_binding.h results in NULL being
re-defined. Thus, include stddef.h in soc_binding.h to avoid having
users include stddef.h along with soc_binding.h.
Change-Id: I600083c5d8f672518beaa1119f14f67728a433aa
Signed-off-by: Furquan Shaikh <furquan@chromium.org>
Reviewed-on: https://review.coreboot.org/17773
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@chromium.org>