gsk: Add missing cicp transfer functions

This was overlooked in 50ea9450ea.

gsk/gpu/shaders/gskgpuconvertcicp.glsl

@@ -176,6 +176,30 @@ bt709_oetf (float v)
     return 1.099  * pow (v, 0.45) - 0.099;
 }
 
+float
+gamma22_oetf (float v)
+{
+  return pow (v, 1.0 / 2.2);
+}
+
+float
+gamma22_eotf (float v)
+{
+  return pow (v, 2.2);
+}
+
+float
+gamma28_oetf (float v)
+{
+  return pow (v, 1.0 / 2.8);
+}
+
+float
+gamma28_eotf (float v)
+{
+  return pow (v, 2.8);
+}
+
 float
 hlg_eotf (float v)
 {
@@ -216,6 +240,16 @@ apply_cicp_eotf (vec3 color,
                    bt709_eotf (color.g),
                    bt709_eotf (color.b));
 
+    case 4u:
+      return vec3 (gamma22_eotf (color.r),
+                   gamma22_eotf (color.g),
+                   gamma22_eotf (color.b));
+
+    case 5u:
+      return vec3 (gamma28_eotf (color.r),
+                   gamma28_eotf (color.g),
+                   gamma28_eotf (color.b));
+
     case 8u:
       return color;
 
@@ -253,6 +287,16 @@ apply_cicp_oetf (vec3 color,
                    bt709_oetf (color.g),
                    bt709_oetf (color.b));
 
+    case 4u:
+      return vec3 (gamma22_oetf (color.r),
+                   gamma22_oetf (color.g),
+                   gamma22_oetf (color.b));
+
+    case 5u:
+      return vec3 (gamma28_oetf (color.r),
+                   gamma28_oetf (color.g),
+                   gamma28_oetf (color.b));
+
     case 8u:
       return color;