EDAC, mv64x60: Fix an error handling path

EDAC, mv64x60: Fix an error handling path

BugLink: http://bugs.launchpad.net/bugs/1763366
[ Upstream commit 68fa24f9121c04ef146b5158f538c8b32f285be5 ]

We should not call edac_mc_del_mc() if a corresponding call to
edac_mc_add_mc() has not been performed yet.

So here, we should go to err instead of err2 to branch at the right
place of the error handling path.

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Cc: linux-edac <linux-edac@vger.kernel.org>
Link: http://lkml.kernel.org/r/20180107205400.14068-1-christophe.jaillet@wanadoo.fr
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>