ufs: definitions for phy interface

- Adding some of the definitions missing in unipro.h, including power
  enumeration.
- Read Modify Write Line helper function
- Indication for the type of suspend

Signed-off-by: Dolev Raviv <draviv@codeaurora.org>
Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>
Signed-off-by: Yaniv Gardi <ygardi@codeaurora.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>