block: Do not include rbtree.h in blk-zoned.c

The block zone code does not use RB-tree. So remove the include of
linux/rbtree.h as it is not needed.
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20240222131724.1803520-2-dlemoal@kernel.orgSigned-off-by: Jens Axboe <axboe@kernel.dk>

block/blk-zoned.c

@@ -11,7 +11,6 @@
 
 #include <linux/kernel.h>
 #include <linux/module.h>
-#include <linux/rbtree.h>
 #include <linux/blkdev.h>
 #include <linux/blk-mq.h>
 #include <linux/mm.h>