EDAC/thunderx: Remove irrelevant variable from error messages

'ret' is irrelevant (it is 0) for both dev_err() calls, so just remove
it from the error message.

 [ bp: Massage commit message. ]

Fixes: 41003396 ("EDAC, thunderx: Add Cavium ThunderX EDAC driver")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/0c046ef5cfb367a3f707ef4270e21a2bcbf44952.1620280098.git.christophe.jaillet@wanadoo.fr