Since SD Physical Layer specification V3.0, AU_SIZE is supported up
to 0xf.  So If SD-card is supported v3.0, then max_au should be 0xf.
Signed-off-by: NJaehoon Chung <jh80.chung@samsung.com>
Signed-off-by: NKyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: NChris Ball <cjb@laptop.org>