checkpatch_presubmit: Skip all merge commits

Bug: 341570880
Test: Verified that checkpatch is skipped for merge commits.
Test: Verified that checkpatch is not skipped for non-merge commits.
Change-Id: Ibc21d8c63a376d423ddc4cb1a1972309c0fc07d4
Signed-off-by: Erik Staats <estaats@google.com>
1 file changed