test-iosched: ufs_test: fix gendisk usage in test

Adding a new access api for gendisk without using scsi private
headers.
This patch fixes multiple errors:
1. Relative include path in ufs_test.c to <../sd.h>
2. Allowing suspend after first test run.

Change-Id: I152d34667ab63790b643abb55111fc5b67c90ac9
Signed-off-by: Dolev Raviv <draviv@codeaurora.org>