x86, mce: Rename MSR_IA32_MCx_CTL2 value

Rename CMCI_EN to MCI_CTL2_CMCI_EN and CMCI_THRESHOLD_MASK to
MCI_CTL2_CMCI_THRESHOLD_MASK to make naming consistent.

Signed-off-by: Huang Ying <ying.huang@intel.com>
LKML-Reference: <1275977348.3444.659.camel@yhuang-dev.sh.intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>