KVM: arm64: vgic-its: Test for valid IRQ in its_sync_lpi_pending_table()

commit 8d3a7dfb upstream.

vgic_get_irq() may not return a valid descriptor if there is no ITS that
holds a valid translation for the specified INTID. If that is the case,
it is safe to silently ignore it and continue processing the LPI pending
table.

Cc: stable@vger.kernel.org
Fixes: 33d3bc95

 ("KVM: arm64: vgic-its: Read initial LPI pending table")
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20240221092732.4126848-2-oliver.upton@linux.dev
Signed-off-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>