ARM: EXYNOS: Add bus clock for FIMD

This patch adds the bus clock for FIMD and changes the device name
for lcd clock

Signed-off-by: Leela Krishna Amudala <l.krishna@samsung.com>
Reviewed-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>