reiserfs: Fix fall-through warnings for Clang

In preparation to enable -Wimplicit-fallthrough for Clang, fix a warning
by explicitly adding a break statement instead of letting the code fall
through to the next case.

Link: https://github.com/KSPP/linux/issues/115
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>

fs/reiserfs/namei.c

@@ -132,6 +132,7 @@ int search_by_entry_key(struct super_block *sb, const struct cpu_key *key,
 			return IO_ERROR;
 		}
 		PATH_LAST_POSITION(path)--;
+		break;
 
 	case ITEM_FOUND:
 		break;