x86/mca: MCA bank clear

x86/mca: MCA bank clear

1). Add explicitly uc=pcc=1 fatal error detect, since under such case
the s/ar/over bits status is undefined and hence may be
mis-cleaned. Explicit fatal detect return 0 indicate stick MSR bank
will have chance to be handled after reboot by polling;
2). Fix a little bug for case SRAR, over bit should be 0 when need
clear bank, otherwise it would reset system;
3). When clear bank, add clear MCi_ADDR/MISC if it's valid, according
to Intel SDM;

Signed-off-by: Liu, Jinsong <jinsong.liu@intel.com>