The entry address for a VM is an IPA.

Change-Id: I9b447796789082c031c8a342a283d3050cf15ccb
diff --git a/src/cpu.c b/src/cpu.c
index 6cd0a2b..d4e7900 100644
--- a/src/cpu.c
+++ b/src/cpu.c
@@ -61,7 +61,7 @@
 /**
  * Turns CPU on and returns the previous state.
  */
-bool cpu_on(struct cpu *c, size_t entry, size_t arg)
+bool cpu_on(struct cpu *c, ipaddr_t entry, size_t arg)
 {
 	bool prev;