fix #29035167

commit 466503d6b1b33be46ab87c6090f0ade6c6011cbc upstream

The following commit introduced a warning on error reports without a
non-zero grain value.

  3724ace582d9 ("EDAC/mc: Fix grain_bits calculation")

The amd64_edac_mod module does not provide a value, so the warning will
be given on the first reported memory error.

Set the grain per DIMM to cacheline size (64 bytes). This is the current
recommendation.

Fixes: 3724ace582d9 ("EDAC/mc: Fix grain_bits calculation")
Signed-off-by: NYazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: NBorislav Petkov <bp@suse.de>
Cc: "linux-edac@vger.kernel.org" <linux-edac@vger.kernel.org>
Cc: James Morse <james.morse@arm.com>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: Robert Richter <rrichter@marvell.com>
Cc: Tony Luck <tony.luck@intel.com>
Link: https://lkml.kernel.org/r/20191022203448.13962-7-Yazen.Ghannam@amd.comSigned-off-by: NZelin Deng <zelin.deng@linux.alibaba.com>
Reviewed-by: NArtie Ding <artie.ding@linux.alibaba.com>