hv: fix possible buffer overflow in 'vcpu_set_eoi_exit()'

 'vector' should be no greater than 0xff,else
 'eoi_exit_bitmap[]' will overflow.

Tracked-On: #1252
Signed-off-by: Yonghua Huang <yonghua.huang@intel.com>
Acked-by: Eddie Dong <eddie.dong@intel.com>

Author: yonghuah

hypervisor/arch/x86/guest/vcpu.c

@@ -145,7 +145,7 @@ void vcpu_set_eoi_exit(struct acrn_vcpu *vcpu, uint32_t vector)
 	pr_dbg("%s", __func__);
 
 	if (bitmap_test_and_set_nolock((uint16_t)(vector & 0x3fU),
-			&(vcpu->arch.eoi_exit_bitmap[vector >> 6U]))) {
+			&(vcpu->arch.eoi_exit_bitmap[(vector & 0xffU) >> 6U]))) {
 		pr_warn("Duplicated vector %u vcpu%u", vector, vcpu->vcpu_id);
 	}
 }