arch/x86: Drop uses of ROMCC_BOOTBLOCK

Change-Id: Ia0405fdd448cb31b3c6ca3b3d76e49e9f430bf74
Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/37339
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-by: HAOUAS Elyes <ehaouas@noos.fr>

src/mainboard/Kconfig

@@ -1,9 +1,5 @@
 comment "Important: Run 'make distclean' before switching boards"
 
-if ROMCC_BOOTBLOCK
-comment "Systems with ROMCC bootblocks will be deprecated soon!"
-endif
-
 choice
 	prompt "Mainboard vendor"
 	default VENDOR_EMULATION