With certain kernel config options many omapdrm files fail to compile
due to missing include of linux/gpio/consumer.h and linux/of.h.

This patch adds those includes.
Signed-off-by: NTomi Valkeinen <tomi.valkeinen@ti.com>
Reported-by: NDan Murphy <dmurphy@ti.com>
Reviewed-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>