cifs: Fix memory leak in smb2_set_ea()

This patch fixes a memory leak when doing a setxattr(2) in SMB2+.

Signed-off-by: Paulo Alcantara <palcantara@suse.de>
Cc: stable@vger.kernel.org
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>