drm: shmobile: Switch to drm_crtc_init_with_planes()

The SH-Mobile DRM driver uses the legacy drm_crtc_init(), which
advertizes only the formats in safe_modeset_formats[] (XR24 and AR24) as
being supported.

Switch to drm_crtc_init_with_planes(), and advertize all supported
(A)RGB modes, so we can use RGB565 as the default mode for the console.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/2098de3d33bc479a8569da7dcbafdb685ff0a13a.1684854992.git.geert+renesas@glider.be