drm/i915: Change gamma/degamma_lut_size data type to u32

Currently, data type of gamma_lut_size & degamma_lut_size elements
in intel_device_info is u16, which means it can accommodate maximum
64k values. In case of ICL multisegmented gamma, the size of gamma
LUT is 256K.

This patch changes the data type of both of these elements to u32.

Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Uma Shankar <uma.shankar@intel.com>

V4: Added Uma's r-b.

Reviewed-by: Uma Shankar <uma.shankar@intel.com>
Signed-off-by: Shashank Sharma <shashank.sharma@intel.com>
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1560321900-18318-2-git-send-email-uma.shankar@intel.com