drm: zynq_drm: encoder: Configure encoder in mode_set()

This patch moves the configuring function from commit() to
mode_set(). Actual encoder hardware configurations are done
int mode_set() and commit() basically enables the encoder
pipe.

Signed-off-by: hyun woo kwon <hyunk@xilinx.com>
drm: zynq_drm: crtc: Configure crtc in mode_set()

CRTC hardware configurations are done in mode_set().
commit() enables the VDMA. VMDA works as a swich for whole pipeline
so that configurations can be applied to hardwares in more atomic way.

Signed-off-by: hyun woo kwon <hyunk@xilinx.com>