EDAC, mce_amd: Use cpu_to_node() to find the node ID

Using the homegrown amd_get_nb_id() to find a node ID on AMD was fine
while the L3 to node mapping was 1:1. And Zen topology broke this. So
let's start slowly moving away from it and use the topology interfaces
instead.

Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Cc: linux-edac <linux-edac@vger.kernel.org>
Cc: x86-ml <x86@kernel.org>
Link: http://lkml.kernel.org/r/1490041614-90057-2-git-send-email-Yazen.Ghannam@amd.com
[ Massage commit message. ]
Signed-off-by: Borislav Petkov <bp@suse.de>

drivers/edac/mce_amd.c

@@ -878,12 +878,8 @@ static void decode_smca_errors(struct mce *m)
 		pr_cont("%s.\n", smca_mce_descs[bank_type].descs[xec]);
 	}
 
-	/*
-	 * amd_get_nb_id() returns the last level cache id.
-	 * The last level cache on Fam17h is 1 level below the node.
-	 */
 	if (bank_type == SMCA_UMC && xec == 0 && decode_dram_ecc)
-		decode_dram_ecc(amd_get_nb_id(m->extcpu) >> 1, m);
+		decode_dram_ecc(cpu_to_node(m->extcpu), m);
 }
 
 static inline void amd_decode_err_code(u16 ec)