fix(gic600): implement workaround to forward highest priority interrupt

If the interrupt being targeted is released from the CPU before the
CLEAR command is sent to the CPU then a subsequent SET command may not
be delivered in a finite time. To workaround this, issue an unblocking
event by toggling GICR_CTLR.DPG* bits after clearing the cpu group
enable (EnableGrp* bits of GIC CPU interface register)
This fix is implemented as per the errata 2384374-part 2 workaround
mentioned here:
https://developer.arm.com/documentation/sden892601/latest/

Change-Id: I13926ceeb7740fa4c05cc5b43170e7ce49598f70
Signed-off-by: Manish V Badarkhe <Manish.Badarkhe@arm.com>
6 files changed