EDAC, altera: Fix error handling path in altr_edac_device_probe()

Return the proper error value if devm_ioremap() fails (and not 0).

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Acked-by: Thor Thayer <thor.thayer@linux.intel.com>
Cc: linux-edac <linux-edac@vger.kernel.org>
Link: http://lkml.kernel.org/r/20170816050506.14541-1-christophe.jaillet@wanadoo.fr


[ Massage commit message. ]
Signed-off-by: Borislav Petkov <bp@suse.de>