mesa/readpixels: check strides are equal before skipping conversion
The CTS packed_pixels test checks that readpixels doesn't write into the space between rows, however we fail that here unless we check the format and stride match. This fixes all the core mesa problems with CTS packed_pixels tests. Cc: "11.0" <mesa-stable@lists.freedesktop.org> Reviewed-by:Iago Toral Quiroga <itoral@igalia.com> Signed-off-by:
Dave Airlie <airlied@redhat.com>