drm/prime: fix to check return of dma_map_sg in prime helper
drm/prime: fix to check return of dma_map_sg in prime helper

The dma_map_sg(), in map_dma_buf callback operation of prime helper,
can return 0 when it fails to map, so it needs to release related
resources.

Signed-off-by: YoungJun Cho <25faea15f7ca65ff494bd1bddb0a00c8c45942d9@samsung.com>
Signed-off-by: Seung-Woo Kim <f0452ad01023e1e19deb03356bab8e3b5dbc61a6@samsung.com>
Signed-off-by: Kyungmin Park <504c23c4986a3760712724894be3105092c27331@samsung.com>
Signed-off-by: Dave Airlie <f2295d84e358395675bc8031be58672073ae065e@redhat.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs