At present, the GIC drivers enable Group 0 interrupts only if there are
Secure SPIs listed in the interrupt properties/list. This means that,
even if there are Group 0 SGIs/PPIs configured, the group remained
disabled in the absence of a Group 0 SPI.

Modify both GICv2 and GICv3 SGI/PPI configuration to enable Group 0 when
corresponding SGIs/PPIs are present.

Change-Id: Id123e8aaee0c22b476eebe3800340906d83bbc6d
Signed-off-by: Jeenu Viswambharan <jeenu.viswambharan@arm.com>