dma-buf: use atomic64_inc_return() in dma_buf_getfile()

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.

Link: https://lkml.kernel.org/r/20241007083921.47525-1-ubizjak@gmail.com


Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: "Christian König" <christian.koenig@amd.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>