The HMC error interrupt would generate an un-necessary message
"unhandled interrupt", causing extra log spam, in addition to causing
a reset that was not necessary.  Prevent this issue by handling the
HMC error case explicitly, and only reset if the interrupt was from
some of the other causes.

Change-Id: Iabd203ba1dfc26a136b638597f3e9991acfa29f3
Signed-off-by: Shannon Nelson <shannon.nelson@intel.com>
Signed-off-by: Anjali Singhai Jain <anjali.singhai@intel.com>
Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Tested-by: Kavindya Deegala <kavindya.s.deegala@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>