arch/x86: Remove ID_SECTION_OFFSET

The location is hardcoded inside flashrom and FILO.
Only two offsets are supported, 0x10 and 0x80.

Change-Id: I8348f2ac0cab969ab78ecb50a55de486eee0cf9b
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/47598
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/arch/x86/Kconfig

@@ -186,10 +186,6 @@ config HPET_ADDRESS
 	hex
 	default 0xfed00000 if !HPET_ADDRESS_OVERRIDE
 
-config ID_SECTION_OFFSET
-	hex
-	default 0x80
-
 # 64KiB default bootblock size
 config C_ENV_BOOTBLOCK_SIZE
 	hex