EDAC, mce_amd_inj: Read out number of MCE banks from the hardware

EDAC, mce_amd_inj: Read out number of MCE banks from the hardware

The number of banks for a given processor is encoded in
MSR_IA32_MCG_CAP[7:0]. So obtain the value from that MSR and use it for
sanity checking in inj_bank_set() instead of doing a family/model check.

Signed-off-by: Aravind Gopalakrishnan <Aravind.Gopalakrishnan@amd.com>
Cc: linux-edac <linux-edac@vger.kernel.org>
Cc: mchehab@osg.samsung.com
Link: http://lkml.kernel.org/r/1432753418-2985-3-git-send-email-Aravind.Gopalakrishnan@amd.com
Signed-off-by: Borislav Petkov <bp@suse.de>