Use atomic64_inc_return(&ref) instead of atomic64_add_return(1, &ref)
to use optimized implementation and ease register pressure around
the primitive for targets that implement optimized variant.
Signed-off-by: Uros Bizjak <ubizjak@xxxxxxxxx>
Cc: Song Liu <song@xxxxxxxxxx>
Cc: Yu Kuai <yukuai3@xxxxxxxxxx>