gl_texture_cache: Use Snorm internal format for ABGR8S

src/video_core/renderer_opengl/gl_texture_cache.cpp

@@ -44,7 +44,7 @@ struct FormatTuple {
 
 constexpr std::array<FormatTuple, VideoCore::Surface::MaxPixelFormat> tex_format_tuples = {{
     {GL_RGBA8, GL_RGBA, GL_UNSIGNED_INT_8_8_8_8_REV, false},                        // ABGR8U
-    {GL_RGBA8, GL_RGBA, GL_BYTE, false},                                            // ABGR8S
+    {GL_RGBA8_SNORM, GL_RGBA, GL_BYTE, false},                                      // ABGR8S
     {GL_RGBA8UI, GL_RGBA_INTEGER, GL_UNSIGNED_BYTE, false},                         // ABGR8UI
     {GL_RGB565, GL_RGB, GL_UNSIGNED_SHORT_5_6_5_REV, false},                        // B5G6R5U
     {GL_RGB10_A2, GL_RGBA, GL_UNSIGNED_INT_2_10_10_10_REV, false},                  // A2B10G10R10U