soc/intel/skylake: Drop FSP_CAR options

It's not implemented for Skylake, all combinations that try to enable it
either result in Kconfig or linker errors.

Move `config SKIP_FSP_CAR` into drivers/intel/fsp1_1 where it's
effective.

TEST=Built Intel/Kunimitsu (FSP1.1) and Intel/KBLRVP8 (FSP2.0) default
     configs with and without this patch: binaries stay the same.

Change-Id: Iae0a2d2c7fd7a71ed24118564e6080c4789cda28
Signed-off-by: Nico Huber <nico.huber@secunet.com>
Reviewed-on: https://review.coreboot.org/c/29533
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>

src/drivers/intel/fsp1_1/Kconfig

@@ -94,4 +94,9 @@ config RESET_ON_INVALID_RAMSTAGE_CACHE
 	bool "Reset the system on S3 wake when ramstage cache invalid."
 	default n
 
+config SKIP_FSP_CAR
+	def_bool n
+	help
+	  Selected by platforms that implement their own CAR setup.
+
 endif #PLATFORM_USES_FSP1_1