Add BGR5A1 Image Format (#495)

* Add `BGR5A1` to ImageUtils.cs

Add `BGR5A1` Image Format.

* Add BGR5A1 to OGLEnumConverter.cs

Ryujinx.Graphics/Gal/OpenGL/OGLEnumConverter.cs

@@ -151,6 +151,7 @@ namespace Ryujinx.Graphics.Gal.OpenGL
                 case GalImageFormat.R32       | GalImageFormat.Float: return (PixelInternalFormat.R32f,         PixelFormat.Red,         PixelType.Float);
                 case GalImageFormat.R32       | GalImageFormat.Sint:  return (PixelInternalFormat.R32i,         PixelFormat.Red,         PixelType.Int);
                 case GalImageFormat.R32       | GalImageFormat.Uint:  return (PixelInternalFormat.R32ui,        PixelFormat.Red,         PixelType.UnsignedInt);
+                case GalImageFormat.BGR5A1    | GalImageFormat.Unorm: return (PixelInternalFormat.Rgb5A1,       PixelFormat.Rgba,        PixelType.UnsignedShort5551);
                 case GalImageFormat.RGB5A1    | GalImageFormat.Unorm: return (PixelInternalFormat.Rgb5A1,       PixelFormat.Rgba,        PixelType.UnsignedShort1555Reversed);
                 case GalImageFormat.RGB565    | GalImageFormat.Unorm: return (PixelInternalFormat.Rgba,         PixelFormat.Rgb,         PixelType.UnsignedShort565Reversed);
                 case GalImageFormat.RG16      | GalImageFormat.Float: return (PixelInternalFormat.Rg16f,        PixelFormat.Rg,          PixelType.HalfFloat);

Ryujinx.Graphics/Texture/ImageUtils.cs

@@ -102,6 +102,7 @@ namespace Ryujinx.Graphics.Texture
             { GalImageFormat.RGBA4,       new ImageDescriptor(2,  1,  1,  TargetBuffer.Color) },
             { GalImageFormat.BptcSfloat,  new ImageDescriptor(16, 4,  4,  TargetBuffer.Color) },
             { GalImageFormat.BptcUfloat,  new ImageDescriptor(16, 4,  4,  TargetBuffer.Color) },
+            { GalImageFormat.BGR5A1,      new ImageDescriptor(2,  1,  1,  TargetBuffer.Color) },
             { GalImageFormat.RGB5A1,      new ImageDescriptor(2,  1,  1,  TargetBuffer.Color) },
             { GalImageFormat.RGB565,      new ImageDescriptor(2,  1,  1,  TargetBuffer.Color) },
             { GalImageFormat.BptcUnorm,   new ImageDescriptor(16, 4,  4,  TargetBuffer.Color) },