[PATCH] s390: fail-fast requests on quiesced devices

Using the fail-fast flag in i/o requests on a dasd disk which has been
quiesced leads to kernel panics.  Modify the request start function to only
work on requests in a valid state.

Signed-off-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>