dt-bindings: media: sun4i-csi: Drop the module clock

It turns out that what was thought to be the module clock was actually the
clock meant to be used by the sensor, and isn't playing any role with the
CSI controller itself. Let's drop that clock from our binding.

Fixes: c5e8f4cc ("media: dt-bindings: media: Add Allwinner A10 CSI binding")
Reported-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <mripard@kernel.org>