EDAC, mpc85xx: Drop setting/clearing RFXE bit in HID1

EDAC, mpc85xx: Drop setting/clearing RFXE bit in HID1

On e500v1, read fault exception enable (RFXE) controls whether assertion
of core_fault_in causes a machine check interrupt. Assertion of
core_fault_in can result from uncorrectable data error, such as an L2
multi-bit ECC error. It can also occur from a system error if logic on
the integrated device signals a fault for nonfatal errors. RFXE bit is
cleared out of reset, and should be left clear for normal operation.
Assertion of core_fault_in does not cause a machine check.

RFXE is set specifically for RIO (Rapid IO) and PCI for book E to catch
the errors by machine check. With this bit set, the EDAC driver can't
get the interrupt in case of uncorrectable error. So this bit is cleared
in favor of EDAC. However, the benefit of catching such uncorrectable
error doesn't outweigh the other errors which may hang the system.
Besides, e500v2 has different errors masked by RFXE, and e500mc doesn't
support this bit. It is more reasonable to leave RFXE as is in the EDAC
driver, and leave the uncorrectable errors triggering machine check for
e500v1.

Suggested-by: Scott Wood <oss@buserror.net>
Signed-off-by: York Sun <york.sun@nxp.com>
Cc: Johannes Thumshirn <morbidrsa@gmail.com>
Cc: linux-edac <linux-edac@vger.kernel.org>
Cc: oss@buserror.net
Cc: stuart.yoder@nxp.com
Link: http://lkml.kernel.org/r/1470779760-16483-2-git-send-email-york.sun@nxp.com
Signed-off-by: Borislav Petkov <bp@suse.de>