ARM: EXYNOS4: Add platform device and helper functions for FIMD

This patch adds platform device s5p_device_fimd0 for EXYNOS4 FIMD0.
EXYNOS4 has two FIMDs(FIMD0, FIMD1). FIMD1 will be added later.
Some definitions used to enable EXYNOS4 FIMD0 are added.

Signed-off-by: Jonghun Han <jonghun.han@samsung.com>
Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>