drm/sun4i: Drop useless assignment in sun4i_layers_init

The assignment found in the main loop in sun4i_layers_init:

	struct sun4i_layer *layer = layers[i];

is useless as it gets overwritten by the next line:

	layer = sun4i_layer_init_one(drm, plane);

Drop the assignment.

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