Fix many warnings with incorrect endian assumptions
which makes the code unportable to new architectures.

The UFS specification defines the byte order as big-endian
for UPIU structure and little-endian for the host controller
transfer/task management descriptors.
Signed-off-by: NSujit Reddy Thumma <sthumma@codeaurora.org>
Acked-by: NVinayak Holikatti <vinholikatti@gmail.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>