bcache:: fix repeated words in comments

Delete the redundant word 'we'.
Signed-off-by: Jilin Yuan <yuanjilin@cdjrlc.com>
Signed-off-by: Coly Li <colyli@suse.de>
Link: https://lore.kernel.org/r/20220919161647.81238-5-colyli@suse.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

drivers/md/bcache/bcache.h

@@ -107,7 +107,7 @@
  *
  * BTREE NODES:
  *
- * Our unit of allocation is a bucket, and we we can't arbitrarily allocate and
+ * Our unit of allocation is a bucket, and we can't arbitrarily allocate and
  * free smaller than a bucket - so, that's how big our btree nodes are.
  *
  * (If buckets are really big we'll only use part of the bucket for a btree node