UBI: avoid unnecessary division operations

UBI already checks that @min io size is the power of 2 at io_init.
It is save to use bit operations then.

Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
8 files changed