video: exynos_dp: Remove unused variable disp_info

Remove unused variable disp_info to fix the following compilation warning:
exynos_dp.c: In function 'exynos_init_dp':
exynos_dp.c:860:23: warning: variable 'disp_info' set but not used
[-Wunused-but-set-variable]

Signed-off-by: Ajay Kumar <ajaykumar.rs@samsung.com>
Signed-off-by: Minkyu Kang <mk7.kang@samsung.com>