as: Fix issue reported by coverity in drivers/block/as-iosched.c

This fixes an issue found in drivers/block/as-iosched.c by Coverity.

Error reported:
CID: 3167
Checker: FORWARD_NULL (help)
File: /export2/p4-coverity/mc2/linux26/drivers/block/as-iosched.c
Function: as_insert_request
Description: Variable "arq" tracked as NULL was passed to a function that dereferences it.

Patch description:
It looks as if the code already assumes that arq != NULL. If arq == NULL, it should crash later where arq is dereferenced(e.g. as_add_request) without checking. Removed the NULL check.

---

 as-iosched.c |   10 ++++------
 1 files changed, 4 insertions(+), 6 deletions(-)

@@ -1513,13 +1513,11 @@
 	struct as_data *ad = q->elevator->elevator_data;
 	struct as_rq *arq = RQ_DATA(rq);
 
-	if (arq) {
-		if (arq->state != AS_RQ_PRESCHED) {
-			printk("arq->state: %d\n", arq->state);
-			WARN_ON(1);
-		}
-		arq->state = AS_RQ_NEW;
+	if (arq->state != AS_RQ_PRESCHED) {
+		printk("arq->state: %d\n", arq->state);
+		WARN_ON(1);
 	}
+	arq->state = AS_RQ_NEW;
 
 	/* barriers must flush the reorder queue */
 	if (unlikely(rq->flags & (REQ_SOFTBARRIER | REQ_HARDBARRIER)