ARM: sunxi: dt: Add sample and output mmc clocks

Add the sample and output clocks for the MMC phase support.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Reviewed-by: Chen-Yu Tsai <wens@csie.org>
Tested-by: Chen-Yu Tsai <wens@csie.org>