arch/x86: Make postcar TempRamExit call generic

Move the FSP-specific call for tearing down cache-as-RAM out of
postcar.c and replace it with an empty weak function.

This patch omits checking if (IS_ENABLED(CONFIG_FSP_CAR)).  The
temp_ram_exit.c file with the real fsp_temp_ram_exit() is only built
when CONFIG_FSP_CAR is true.

Change-Id: I9adbb1f2a7b2ff50d9f36d5a3640f63410c09479
Signed-off-by: Marshall Dawson <marshalldawson3rd@gmail.com>
Reviewed-on: https://review.coreboot.org/20965
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
3 files changed