drm/exynos: Fix typo in exynos_mixer.c
drm/exynos: Fix typo in exynos_mixer.c

Correct spelling "sucessful" to "successful" in
drivers/gpu/drm/exynos/exynos_mixer.c

Signed-off-by: Masanari Iida <f31bb8ac2957d045575b3081e813605474613a21@gmail.com>
Signed-off-by: Inki Dae <bae4a7a27bbc965064e97edd6e179ac4979db440@samsung.com>
Signed-off-by: Kyungmin Park <504c23c4986a3760712724894be3105092c27331@samsung.com>

KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs