HV: remove unused INVALID_VM_ID

The VM IDs which is high or equal then CONFIG_MAX_VM_NUM are all
invalid VM IDs, the MACRO has never been referenced in code, so
remove it;

Tracked-On: #3214

Signed-off-by: Victor Sun <victor.sun@intel.com>
Reviewed-by: Jason Chen CJ <jason.cj.chen@intel.com>

Author: jsun26intel

hypervisor/include/arch/x86/guest/vm.h

@@ -27,8 +27,6 @@
 #include <e820.h>
 #include <vm_config.h>
 
-#define INVALID_VM_ID 0xffffU
-
 struct vm_hw_info {
 	/* vcpu array of this VM */
 	struct acrn_vcpu vcpu_array[CONFIG_MAX_VCPUS_PER_VM];