bfs: bfad_worker cleanup

This kthread is not loop at all due to break at the end of the loop.  Make
that function linear, with no while loop.

And remove an unnecessary cast.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Anil Gurumurthy <anil.gurumurthy@qlogic.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>