arch/x86: Make mb/romstage.c optional

Currently src/mainboard/*/romstage.c is mandatory for compiling,
this makes having the file present even though there is nothing to
initialize in romstage on the mainboard side. Eliminate the need to
have empty romstage.c files using the wildcard function.

BUG=None
BRANCH=None
TEST= build cannonlake_rvp after removing the romstage.c file.

Change-Id: Id6335a473d413d1aa89389d3a3d174ed4a1bda90
Signed-off-by: Rizwan Qureshi <rizwan.qureshi@intel.com>
Reviewed-on: https://review.coreboot.org/28849
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Subrata Banik <subrata.banik@intel.com>

0 files changed, 0 insertions, 0 deletions