KVM: selftests: aarch64: Cmdline arg to set EOI mode in vgic_irq

Add a new cmdline arg to set the EOI mode for all vgic_irq tests.  This
specifies whether a write to EOIR will deactivate IRQs or not.

Signed-off-by: Ricardo Koller <ricarkol@google.com>
Acked-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211109023906.1091208-10-ricarkol@google.com