i7core_edac: Add edac_mce glue

Adds a glue code to allow i7core to work with mcelog. With the glue,
i7core registers itself on edac_mce. At mce, when an error is detected,
it calls all registered drivers (in this case, i7core), for EDAC error
handling.

TODO: It currently just prints the MCE error log using about the same
      format as mce panic messages. The error message should be enhanced
      with mcelog userspace info and converted into the proper EDAC format,
      to feed the EDAC error counts.

Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>