hw/ufs: ufs attribute read/write test implemented

hw/ufs: ufs attribute read/write test implemented

New test function "ufstest_query_attr_request" added, which can check one's
virtual UFS device can properly read and write its attribute data.
It tests if reading and writing attributes work properly. There are
some testcases that are intended to make an error caused by writing an
invalid value, allocating an invalid selector and permission issues.

Signed-off-by: Yoochan Jeong <yc01.jeong@samsung.com>
Reviewed-by: Jeuk Kim <jeuk20.kim@samsung.com>
Signed-off-by: Jeuk Kim <jeuk20.kim@samsung.com>