Sed-opal Fixes

[Scott Bauer]

changes from v3->v4:

Changed manual kzalloc + copy from user to memdup_user.

This small series fixes a small ABI issue when using the _IOC_SIZE
with the Activate Locking SP ioctl. I had put the wrong structure
in the IOW macro in the uapi header which caused issues when trying
to copy in the contents for the command.