drm/exynos: add error check routine in exynos_drm_open
drm/exynos: add error check routine in exynos_drm_open

When the exynos_drm_subdrv_open() returns error, the file_priv
should be released and file->driver_priv set to NULL.

Signed-off-by: YoungJun Cho <25faea15f7ca65ff494bd1bddb0a00c8c45942d9@samsung.com>
Signed-off-by: Kyungmin Park <504c23c4986a3760712724894be3105092c27331@samsung.com>
Signed-off-by: Inki Dae <bae4a7a27bbc965064e97edd6e179ac4979db440@samsung.com>

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