libweston: Drop requirement of setting mm_width/mm_height in backends

They were required for transitional phase in order not to
break previous weston_output_init(). Now, they can even
be initialized on enable, or left with defaults if backend
doesn't support them.

Reviewed-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
Signed-off-by: Armin Krezović <krezovic.armin@gmail.com>
1 file changed