[BLOCK] Get rid of request_queue_t typedef

Some of the code has been gradually transitioned to using the proper
struct request_queue, but there's lots left. So do a full sweet of
the kernel and get rid of this typedef and replace its uses with
the proper type.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/drivers/block/xd.h b/drivers/block/xd.h
index 82e090f..cffd44a 100644
--- a/drivers/block/xd.h
+++ b/drivers/block/xd.h
@@ -104,7 +104,7 @@
 static u_char xd_detect (u_char *controller, unsigned int *address);
 static u_char xd_initdrives (void (*init_drive)(u_char drive));
 
-static void do_xd_request (request_queue_t * q);
+static void do_xd_request (struct request_queue * q);
 static int xd_ioctl (struct inode *inode,struct file *file,unsigned int cmd,unsigned long arg);
 static int xd_readwrite (u_char operation,XD_INFO *disk,char *buffer,u_int block,u_int count);
 static void xd_recalibrate (u_char drive);