linux-phytec-fsl

UBI: trivial: fix comment of ubi_calculate_reserved function

The function name within the comment was not aligned with the actual
function name.

Signed-off-by: Shmulik Ladkani <shmulik.ladkani@gmail.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@linux.intel.com>