x86/mca: simplify mce action, and some update of mem err handler for

x86/mca: simplify mce action, and some update of mem err handler for
future SRAR extension

This patch simplify mce_action(). Basically the 2 set of mce status
flags MCA_... and MCER_... are highly functional similar. This patch
remove the redundant middle-level flag MCA_..., and its related data
structure and function, so that mce_action() logic is more clean and
simpler.  This patch also update mem err
handler. intel_memerr_dhandler() will be commonly used by SRAO and
SRAR, so for the extension of future SRAR case, this patch remove the
default fail flag from intel_memerr_dhandler() outside to SRAO/SRAR
level, since only SRAO/SRAR handler itself has the knowledge of how to
handle the failure when mem err handler fail.

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