gralloc: Sort usage flags

Sorts the usage flags in increasing order so it's easier to see where
the gaps are.

Bug: 21609491
Change-Id: I98af3c67be84c6c5137767f3cd7a8bd63dfb5c03
(cherry picked from commit fd2d859445d614ab3f6c4687de839097566ac317)
1 file changed