drm/exynos: remove the redundant machine checking code

This code is unnecessary, because same logic is already included. Refer
this mail thread[1] for detail.

[1] http://lists.freedesktop.org/archives/dri-devel/2015-January/075132.html

Signed-off-by: Hyungwon Hwang <human.hwang@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>

diff --cc drivers/gpu/drm/exynos/exynos_drm_drv.c
Simple merge