ACPI: Remove Kconfig COMMON_FADT

Also remove default mb/*/fadt.c from Makefiles.

Change-Id: I6a2839c524f8311ec9a382a84066afc7d579eaca
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/41948
Reviewed-by: HAOUAS Elyes <ehaouas@noos.fr>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/soc/amd/picasso/Kconfig

@@ -55,7 +55,6 @@ config CPU_SPECIFIC_OPTIONS
 	select UDK_2017_BINDING
 	select CACHE_MRC_SETTINGS
 	select HAVE_CF9_RESET
-	select COMMON_FADT
 
 config PRERAM_CBMEM_CONSOLE_SIZE
 	hex