Fix common misspellings

Fixes generated by 'codespell' and manually reviewed.

Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
diff --git a/fs/block_dev.c b/fs/block_dev.c
index c1511c6..5147bdd 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -653,7 +653,7 @@
  * @whole: whole block device containing @bdev, may equal @bdev
  * @holder: holder trying to claim @bdev
  *
- * Test whther @bdev can be claimed by @holder.
+ * Test whether @bdev can be claimed by @holder.
  *
  * CONTEXT:
  * spin_lock(&bdev_lock).