Use uint32_t rather than int for memory modes.

Change-Id: I12b4d0cb0582d80bf86ca5dd99c7e462d776320f
diff --git a/src/arch/aarch64/hypervisor/handler.c b/src/arch/aarch64/hypervisor/handler.c
index 8132406..77b10e3 100644
--- a/src/arch/aarch64/hypervisor/handler.c
+++ b/src/arch/aarch64/hypervisor/handler.c
@@ -528,7 +528,8 @@
  * instruction and data aborts, but not necessarily for other exception reasons.
  */
 static struct vcpu_fault_info fault_info_init(uintreg_t esr,
-					      const struct vcpu *vcpu, int mode)
+					      const struct vcpu *vcpu,
+					      uint32_t mode)
 {
 	uint32_t fsc = esr & 0x3f;
 	struct vcpu_fault_info r;