arm: vgic: Out-of-bound access when sending SGIs

ISSUE DESCRIPTION ARM guests can send SGI i.e. IPI targeting a list of vCPUs using the MMIO register GICDSGIR GICv2 or System Register ICCSGI1R GICv3. However, the emulation code does not sanitize the list and will directly access an array without checking whether the array index is within bounds...