drm/amd/display: Add simple struct doc to remove doc build warning

This commit is a part of a series that addresses the following build
warning for opp:

./drivers/gpu/drm/amd/display/dc/inc/hw/opp.h:1: warning: no structured
comments found
./drivers/gpu/drm/amd/display/dc/inc/hw/dpp.h:1: warning: no structured
comments found

This commit fixes this issue by adding a simple kernel-doc to a struct
in the opp.h and the dpp.h files.

Cc: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/inc/hw/dpp.h

@@ -147,16 +147,28 @@ struct cnv_color_keyer_params {
 	int color_keyer_blue_high;
 };
 
-/* new for dcn2: set the 8bit alpha values based on the 2 bit alpha
- *ALPHA_2BIT_LUT. ALPHA_2BIT_LUT0   default: 0b00000000
- *ALPHA_2BIT_LUT. ALPHA_2BIT_LUT1   default: 0b01010101
- *ALPHA_2BIT_LUT. ALPHA_2BIT_LUT2   default: 0b10101010
- *ALPHA_2BIT_LUT. ALPHA_2BIT_LUT3   default: 0b11111111
+/**
+ * struct cnv_alpha_2bit_lut - Set the 8bit alpha values based on the 2 bit alpha
  */
 struct cnv_alpha_2bit_lut {
+	/**
+	* @lut0: ALPHA_2BIT_LUT. ALPHA_2BIT_LUT0. Default: 0b00000000
+	*/
 	int lut0;
+
+	/**
+	 * @lut1: ALPHA_2BIT_LUT. ALPHA_2BIT_LUT1. Default: 0b01010101
+	 */
 	int lut1;
+
+	/**
+	 * @lut2: ALPHA_2BIT_LUT. ALPHA_2BIT_LUT2. Default: 0b10101010
+	 */
 	int lut2;
+
+	/**
+	 * @lut3: ALPHA_2BIT_LUT. ALPHA_2BIT_LUT3. Default: 0b11111111
+	 */
 	int lut3;
 };
 

drivers/gpu/drm/amd/display/dc/inc/hw/opp.h

@@ -205,9 +205,24 @@ struct gamma_coefficients {
 	struct fixed31_32 user_brightness;
 };
 
+/**
+ * struct pwl_float_data - Fixed point RGB color
+ */
 struct pwl_float_data {
+	/**
+	 * @r: Component Red.
+	 */
 	struct fixed31_32 r;
+
+	/**
+	 * @g: Component Green.
+	 */
+
 	struct fixed31_32 g;
+
+	/**
+	 * @b: Component Blue.
+	 */
 	struct fixed31_32 b;
 };