libpayload: Check for CBFS_DEFAULT_MEDIA in cbfs_get_file_content()

The error-prone interface of cbfs_get_file_content() led to another
possible NULL dereferencing. So check for CBFS_DEFAULT_MEDIA here
like the other functions do.

Change-Id: Ib8732160d389e9ecceb44f28be0e7de9a1d66e04
Signed-off-by: Nico Huber <nico.huber@secunet.com>
Reviewed-on: http://review.coreboot.org/11796
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
1 file changed