Treat unsized RGBA/RGB textures as renderable.

Bug 28929520

Change-Id: I94fcac3149fafd422e1879360109b668a2ca6029
Reviewed-on: https://swiftshader-review.googlesource.com/5410
Reviewed-by: Nicolas Capens <capn@google.com>
Tested-by: Nicolas Capens <capn@google.com>
diff --git a/src/OpenGL/libGLESv2/utilities.cpp b/src/OpenGL/libGLESv2/utilities.cpp
index 1143546..850c1e2 100644
--- a/src/OpenGL/libGLESv2/utilities.cpp
+++ b/src/OpenGL/libGLESv2/utilities.cpp
@@ -1010,6 +1010,8 @@
 	{
 		switch(internalformat)
 		{
+		case GL_RGB:
+		case GL_RGBA:
 		case GL_RGBA4:
 		case GL_RGB5_A1:
 		case GL_RGB565: