gl-renderer: Make attach_shm return early on cache hit

If we can reuse the textures we already have, just return early, rather
than putting all the work in a large indented body.

Signed-off-by: Daniel Stone <daniels@collabora.com>

libweston/renderer-gl/gl-renderer.c

@@ -2158,13 +2158,16 @@ unsupported:
 	/* Only allocate a texture if it doesn't match existing one.
 	 * If a switch from DRM allocated buffer to a SHM buffer is
 	 * happening, we need to allocate a new texture buffer. */
-	if (pitch != gb->pitch ||
-	    buffer->height != gb->height ||
-	    gl_format[0] != gb->gl_format[0] ||
-	    gl_format[1] != gb->gl_format[1] ||
-	    gl_format[2] != gb->gl_format[2] ||
-	    gl_pixel_type != gb->gl_pixel_type ||
-	    gb->buffer_type != BUFFER_TYPE_SHM) {
+	if (pitch == gb->pitch &&
+	    buffer->height == gb->height &&
+	    gl_format[0] == gb->gl_format[0] &&
+	    gl_format[1] == gb->gl_format[1] &&
+	    gl_format[2] == gb->gl_format[2] &&
+	    gl_pixel_type == gb->gl_pixel_type &&
+	    gb->buffer_type == BUFFER_TYPE_SHM) {
+		return true;
+	}
+
 	gb->pitch = pitch;
 	gb->height = buffer->height;
 	gb->gl_format[0] = gl_format[0];
@@ -2179,7 +2182,6 @@ unsupported:
 	gs->surface = es;
 
 	ensure_textures(gs, GL_TEXTURE_2D, num_planes);
-	}
 
 	return true;
 }