drm/sun4i: Eliminate pointless on stack copy of drm_display_info

Just use a pointer to the display_info rather than make a copy
on stack.

Cc: Maxime Ripard <maxime.ripard@bootlin.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190326173810.11979-1-ville.syrjala@linux.intel.com


Acked-by: Maxime Ripard <maxime.ripard@bootlin.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>