block: don't include blk-mq.h in blk.h

No needed, shift a blk-stat.h include into the source file that needs it
instead.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211123185312.1432157-6-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

block/blk-throttle.c

@@ -13,6 +13,7 @@
 #include <linux/blk-cgroup.h>
 #include "blk.h"
 #include "blk-cgroup-rwstat.h"
+#include "blk-stat.h"
 #include "blk-throttle.h"
 
 /* Max dispatch from a group in 1 round */

block/blk.h

@@ -9,7 +9,6 @@
 #include <linux/memblock.h>	/* for max_pfn/max_low_pfn */
 #include <xen/xen.h>
 #include "blk-crypto-internal.h"
-#include "blk-mq.h"
 
 struct elevator_type;