drm/i915: Add 10bit LUT for ilk/snb

Plop in support for 10bit LUT on ilk/snb.

There is no split gamma mode on these platforms, so we have
to choose between degamma and gamma. That could be a runtime choice
but for now let's just advertize the gamma as having 1024 entries.
We'll also keep the ctm hidden for now.

v2: Don't use I915_WRITE_FW() yet
    Introduce bool has_ctm (Maarten)
    Call drm_crtc_enable_color_mgmt() uncoditionally (Maarten)

Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190401200231.2333-5-ville.syrjala@linux.intel.com
Reviewed-by: Uma Shankar <uma.shankar@intel.com>

drivers/gpu/drm/i915/i915_pci.c

@@ -116,6 +116,8 @@
 		[PIPE_C] = IVB_CURSOR_C_OFFSET, \
 	}
 
+#define ILK_COLORS \
+	.color = { .gamma_lut_size = 1024 }
 #define IVB_COLORS \
 	.color = { .degamma_lut_size = 512, .gamma_lut_size = 512 }
 #define CHV_COLORS \
@@ -332,6 +334,7 @@ static const struct intel_device_info intel_gm45_info = {
 	.has_rc6 = 0, \
 	I9XX_PIPE_OFFSETS, \
 	I9XX_CURSOR_OFFSETS, \
+	ILK_COLORS, \
 	GEN_DEFAULT_PAGE_SIZES
 
 static const struct intel_device_info intel_ironlake_d_info = {
@@ -360,6 +363,7 @@ static const struct intel_device_info intel_ironlake_m_info = {
 	.ppgtt_size = 31, \
 	I9XX_PIPE_OFFSETS, \
 	I9XX_CURSOR_OFFSETS, \
+	ILK_COLORS, \
 	GEN_DEFAULT_PAGE_SIZES
 
 #define SNB_D_PLATFORM \