Coda: mount hangs because of missed REQ_WRITE rename

Coda's REQ_* defines were renamed to avoid clashes with the block layer
(commit 4aeefdc6

: "coda: fixup clash with block layer REQ_*
defines").

However one was missed and response messages are no longer matched with
requests and waiting threads are no longer woken up.  This patch fixes
this.

Signed-off-by: Jan Harkes <jaharkes@cs.cmu.edu>
[ Also fixed up whitespace while at it  -Linus ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>