drm/exynos: clean up register definions for fimd and decon

This patch removes suffixes from I80 relevant register definitions,
which are misleading.

This is based on top of below patch set,
     http://www.spinics.net/lists/dri-devel/msg104057.html

Signed-off-by: Inki Dae <inki.dae@samsung.com>
3 files changed