Get DataType from internal format if there's no hint

* dataType would never have been eGL_NONE previously, since it's either set to
  the hint or eGL_UNSIGNED_BYTE.

renderdoc/driver/gl/gl_initstate.cpp

@@ -552,7 +552,7 @@ void GLResourceManager::CreateTextureImage(GLuint tex, GLenum internalFormat,
     {
       baseFormat = GetBaseFormat(internalFormat);
 
-      if(dataType == eGL_NONE)
+      if(internalFormatHint == eGL_NONE)
         dataType = GetDataType(internalFormat);
     }