drm: Implement the drm_format_*() helpers as drm_format_info() wrappers

Turn the drm_format_*() helpers into wrappers around the drm_format_info
lookup function to centralize all format information in a single place.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Eric Engestrom <eric.engestrom@imgtec.com>
Signed-off-by: Archit Taneja <architt@codeaurora.org>
Link: http://patchwork.freedesktop.org/patch/msgid/1476744081-24485-3-git-send-email-laurent.pinchart@ideasonboard.com