Introduce spci_vm_count_t for count of VMs.

Change-Id: I4eae492136019c6a39b2d06b59793f021b4e07bb
diff --git a/src/api.c b/src/api.c
index 698e788..ccbeeda 100644
--- a/src/api.c
+++ b/src/api.c
@@ -216,7 +216,7 @@
 /**
  * Returns the number of VMs configured to run.
  */
-int64_t api_vm_get_count(void)
+spci_vm_count_t api_vm_get_count(void)
 {
 	return vm_get_count();
 }
diff --git a/src/vm.c b/src/vm.c
index e9919d8..8532144 100644
--- a/src/vm.c
+++ b/src/vm.c
@@ -23,7 +23,7 @@
 #include "vmapi/hf/call.h"
 
 static struct vm vms[MAX_VMS];
-static uint32_t vm_count;
+static spci_vm_count_t vm_count;
 
 bool vm_init(uint32_t vcpu_count, struct mpool *ppool, struct vm **new_vm)
 {
@@ -69,7 +69,7 @@
 	return true;
 }
 
-uint32_t vm_get_count(void)
+spci_vm_count_t vm_get_count(void)
 {
 	return vm_count;
 }