wined3d: Get rid of the mostly unused SRGB_BOTH enum value.

dlls/wined3d/context.c

@@ -2341,14 +2341,8 @@ static void context_setup_target(struct wined3d_device *device,
         {
             /* Read the back buffer of the old drawable into the destination texture. */
             if (context->current_rt->texture_name_srgb)
-            {
-                surface_internal_preload(context->current_rt, SRGB_BOTH);
-            }
-            else
-            {
+                surface_internal_preload(context->current_rt, SRGB_SRGB);
             surface_internal_preload(context->current_rt, SRGB_RGB);
-            }
-
             surface_modify_location(context->current_rt, SFLAG_INDRAWABLE, FALSE);
         }
     }

dlls/wined3d/texture.c

@@ -683,9 +683,6 @@ static void texture2d_preload(struct wined3d_texture *texture, enum WINED3DSRGB
             srgb_mode = FALSE;
             break;
 
-        case SRGB_BOTH:
-            texture2d_preload(texture, SRGB_RGB);
-            /* Fallthrough */
         case SRGB_SRGB:
             srgb_mode = TRUE;
             break;

dlls/wined3d/wined3d_private.h

@@ -1876,7 +1876,6 @@ enum WINED3DSRGB
     SRGB_ANY                                = 0,    /* Uses the cached value(e.g. external calls) */
     SRGB_RGB                                = 1,    /* Loads the rgb texture */
     SRGB_SRGB                               = 2,    /* Loads the srgb texture */
-    SRGB_BOTH                               = 3,    /* Loads both textures */
 };
 
 struct gl_texture