cifs: add replacement for cifs_strtoUCS_le called cifs_from_ucs2

Add a replacement function for cifs_strtoUCS_le. cifs_from_ucs2
takes args for the source and destination length so that we can ensure
that the function is confined within the intended buffers.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Acked-by: Suresh Jayaraman <sjayaraman@suse.de>
Signed-off-by: Steve French <sfrench@us.ibm.com>
diff --git a/fs/cifs/cifs_unicode.h b/fs/cifs/cifs_unicode.h
index d6fe8ec..6aa6533 100644
--- a/fs/cifs/cifs_unicode.h
+++ b/fs/cifs/cifs_unicode.h
@@ -72,6 +72,8 @@
 #endif				/* UNIUPR_NOLOWER */
 
 #ifdef __KERNEL__
+int cifs_from_ucs2(char *to, const __le16 *from, int tolen, int fromlen,
+		   const struct nls_table *codepage, bool mapchar);
 int cifs_strfromUCS_le(char *, const __le16 *, int, const struct nls_table *);
 int cifs_strtoUCS(__le16 *, const char *, int, const struct nls_table *);
 #endif