minigbm: add drv_resolve_format_helper

Removes duplicated code.

BUG=none
TEST=CQ

Change-Id: Iea59cc6ca20e13756b6121db7f5294855cc6cfcd
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/minigbm/+/2672509
Tested-by: Gurchetan Singh <[email protected]>
Reviewed-by: Chad Versace <[email protected]>
Reviewed-by: Jason Macnak <[email protected]>
Reviewed-by: Gurchetan Singh <[email protected]>
Commit-Queue: Gurchetan Singh <[email protected]>
6 files changed