soc/intel/skylake: drop support for FSP 1.1

soc/intel/skylake: drop support for FSP 1.1

This drops support for FSP 1.1 in soc/intel/skylake, after all boards
have been migrated to FSP 2.0, which is backwards compatible.

Any moving of files happens in a follow-up commit to make review easier.

Change-Id: I0dd2eab0edfda0545ff94c3908b8574d5ad830bd
Signed-off-by: Michael Niewöhner <foss@mniewoehner.de>
Signed-off-by: Matt DeVillier <matt.devillier@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/35813
Reviewed-by: Michael Niewöhner
Reviewed-by: Nico Huber <nico.h@gmx.de>
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>