build system: Deal with wildcard in subdirs-y

This enabled subdirs-y += * to work properly.

BUG=b:68384012
BRANCH=none
TEST=Run `abuild -t GOOGLE_CORAL -p none` and observe that
`find coreboot-builds/GOOGLE_CORAL -type d -name '\*'` doesn't return
any files called '*'.

Change-Id: Iba7866db339ae9b4063c4b4377500652eb1be13d
Signed-off-by: Patrick Georgi <pgeorgi@google.com>
Reviewed-on: https://review.coreboot.org/22208
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

0 files changed, 0 insertions, 0 deletions