dri_util: add driImageFormatToSizedInternalGLFormat function

dri_util: add driImageFormatToSizedInternalGLFormat function

This is needed to implement the EXT_EGL_image_storage spec:

"If <target> is GL_TEXTURE_2D, then the resultant texture must have a
sized internal format which is colorspace and size compatible with the
dma-buf.  If the GL is unable to determine such a format, the error
INVALID_OPERATION is generated."

Reviewed-by: Tapani Pälli <tapani.palli@intel.com>