EDAC/mce_amd: Decode MCA_STATUS[Scrub] bit

Previous AMD systems have had a bit in MCA_STATUS to indicate that an
error was detected on a scrub operation. However, this bit was defined
differently within different banks and families/models.

Starting with Family 17h, MCA_STATUS[40] is either Reserved/Read-as-Zero
or defined as "Scrub", for all MCA banks and CPU models. Therefore, this
bit can be defined as the "Scrub" bit.

Define MCA_STATUS[40] as "Scrub" and decode it in the AMD MCE decoding
module for Family 17h and newer systems.

Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Morse <james.morse@arm.com>
Cc: linux-edac <linux-edac@vger.kernel.org>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: Pu Wen <puwen@hygon.cn>
Cc: Qiuxu Zhuo <qiuxu.zhuo@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: x86-ml <x86@kernel.org>
Link: https://lkml.kernel.org/r/20190212212417.107049-1-Yazen.Ghannam@amd.com