glCompressedTexSubImage2D() takes an internalformat parameter which
is already always a sized internal format.

Change-Id: Iaf783e019e08d941053d5f347ee495bdd179f1ce
Reviewed-on: https://swiftshader-review.googlesource.com/17050Tested-by: Nicolas Capens <nicolascapens@google.com>
Reviewed-by: Alexis Hétu <sugoi@google.com>