drm/sun4i: Realign Makefile padding and reorder it

Some options were not padded as they should, and the order in the Makefile
was chaotic. Fix that.

Reviewed-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Link: https://patchwork.freedesktop.org/patch/msgid/9410b284ec97453fa692537dffaaa4fb4833347c.1508231063.git-series.maxime.ripard@free-electrons.com