ARM: EXYNOS: Fix NULL pointer dereference bug in SMDK4X12

ARM: EXYNOS: Fix NULL pointer dereference bug in SMDK4X12

When DRM support for Samsung SoC and Samsung S3C framebuffer support
are selected, the kernel crashes as it does not get the required
platform data. Change the compile macro to CONFIG_DRM_EXYNOS_FIMD
to fix this.

Fixes the following boot time crash:
Unable to handle kernel NULL pointer dereference at virtual address 00000000
PC is at 0x0
LR is at s3c_fb_probe+0x198/0x788
[<c0152270>] (s3c_fb_probe+0x198/0x788) from [<c019e52c>] (platform_drv_probe+0x18/0x1c)
[<c019e52c>] (platform_drv_probe+0x18/0x1c) from [<c019d2e4>] (driver_probe_device+0x70/0x1f0)
[<c019d2e4>] (driver_probe_device+0x70/0x1f0) from [<c019d4f0>] (__driver_attach+0x8c/0x90)
[<c019d4f0>] (__driver_attach+0x8c/0x90) from [<c019bc3c>] (bus_for_each_dev+0x50/0x7c)
[<c019bc3c>] (bus_for_each_dev+0x50/0x7c) from [<c019cb4c>] (bus_add_driver+0x170/0x23c)
[<c019cb4c>] (bus_add_driver+0x170/0x23c) from [<c019d9a4>] (driver_register+0x78/0x144)
[<c019d9a4>] (driver_register+0x78/0x144) from [<c000862c>] (do_one_initcall+0x34/0x174)
[<c000862c>] (do_one_initcall+0x34/0x174) from [<c020ed7c>] (kernel_init+0x100/0x2a0)
[<c020ed7c>] (kernel_init+0x100/0x2a0) from [<c000e118>] (ret_from_fork+0x14/0x3c)

Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>