build system: also use ramstage CPPFLAGS for ACPI

With the SoC header move, we need more fine-grained control
over the search path for ACPI compilation, too.

Change-Id: I65bb9847bbba0d27dfd34da33b290b4ad95bd5e5
Signed-off-by: Patrick Georgi <pgeorgi@chromium.org>
Reviewed-on: http://review.coreboot.org/9362
Tested-by: build bot (Jenkins)
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Aaron Durbin <adurbin@google.com>
1 file changed