crypto: ice: general driver clean-up

* Removed spinlock as it was not locking against anything
* Removed conversion of interrupt status to error number
  as it is not used by API client, and in case several bits are
  set only 1 error is ever handled and the rest get lost.
  Instead pass to the client the complete status.
* Removed redundant includes, variables
* vops structure is returned after performing a lookup in the DTS.
  There's no need for that as we already know the structure
  to return.
* Other minor corrections

Change-Id: I6d2549ce04c9e4b19fdd8fe3dfee03d83bfd9d77
Signed-off-by: Gilad Broner <gbroner@codeaurora.org>