Fix common misspellings

Fixes generated by 'codespell' and manually reviewed.

Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index fbde6f7..4b36ec3 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -3055,7 +3055,7 @@
 	if (ONE_STATEID(stateid) && (flags & RD_STATE))
 		return nfs_ok;
 	else if (locks_in_grace()) {
-		/* Answer in remaining cases depends on existance of
+		/* Answer in remaining cases depends on existence of
 		 * conflicting state; so we must wait out the grace period. */
 		return nfserr_grace;
 	} else if (flags & WR_STATE)
@@ -3675,7 +3675,7 @@
 /*
  * Alloc a lock owner structure.
  * Called in nfsd4_lock - therefore, OPEN and OPEN_CONFIRM (if needed) has 
- * occured. 
+ * occurred. 
  *
  * strhashval = lock_ownerstr_hashval 
  */