drm/i915: Change lfsr_converts[] to u16

All the values in the DSI PLL LFSR seed table fit into 9bits, so change
the type to u16 from u32 to save a bit of space.

 drivers/gpu/drm/i915/i915.ko:
-.rodata                        90824
+.rodata                        90760

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1458052809-23426-10-git-send-email-ville.syrjala@linux.intel.com


Reviewed-by: Jani Nikula <jani.nikula@intel.com>