mca: Allow for passing ECC error record to memory controller driver

Added (de)registration functions for memory controller driver to be
notified when ECC errors occur. This allows for decoding of the
specific error by the driver.

Submitted by: Lakshman Likith Nudurupati <lnlakshman@juniper.net>
Sponsored by: Juniper Networks, Inc.
Obtained from: Semihalf