[media] vivid: Code refactor for color encoding

Replace is_yuv with color_enc Which can be used by other
color encodings such us HSV.

This change should ease the review of the following patches.

Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
diff --git a/include/media/v4l2-tpg.h b/include/media/v4l2-tpg.h
index 329bebf..b4cb8f3 100644
--- a/include/media/v4l2-tpg.h
+++ b/include/media/v4l2-tpg.h
@@ -87,6 +87,11 @@
 	TPG_MOVE_POS_FAST,
 };
 
+enum tgp_color_enc {
+	TGP_COLOR_ENC_RGB,
+	TGP_COLOR_ENC_YCBCR,
+};
+
 extern const char * const tpg_aspect_strings[];
 
 #define TPG_MAX_PLANES 3
@@ -119,7 +124,7 @@
 	u8				saturation;
 	s16				hue;
 	u32				fourcc;
-	bool				is_yuv;
+	enum tgp_color_enc		color_enc;
 	u32				colorspace;
 	u32				xfer_func;
 	u32				ycbcr_enc;