soc/intel/skylake: Remove ROMCCFLAGS

This is never used.

Change-Id: I414acc38f72e206eb48cfd98214985c320862c91
Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/33556
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Patrick Rudolph <siro@das-labor.org>

src/soc/intel/skylake/Makefile.inc

@@ -108,6 +108,4 @@ endif
 # Currently used for microcode path.
 CPPFLAGS_common += -I3rdparty/blobs/mainboard/$(MAINBOARDDIR)
 
-ROMCCFLAGS := -mcpu=p4 -fno-simplify-phi -O2
-
 endif