drm: zynq_drm: drv: Fixed a minor variable declaration

Fix to initialize a variable directly on declaration.

Signed-off-by: hyun woo kwon <hyunk@xilinx.com>
drm: zynq_drm: encoder: Use adjested modes insead of requested modes

Requested modes were used because any of zynq_drm driver doesn't
adjust modes anyway. But using adjusted modes make sense, so fix it.

Signed-off-by: hyun woo kwon <hyunk@xilinx.com>
drm: zynq_drm: Fix some styles

Fix some styles, and change request_irq() to devm_request_irq()
int vtc.c

Signed-off-by: hyun woo kwon <hyunk@xilinx.com>
drm: zynq_drm: Change error return code for deferred probing

Modify to return error codes instead of NULL, so the more proper
error handling can be done. With this patch deferred probing happens
only when subdevice probing fails.

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