x86_64: enable interrupts during pmap_handle_fault

interrupts will need to be enable to allow for requesting missing pages from userspace
services.

arch/x86_64/irq.c

@@ -97,7 +97,9 @@ static void pf_handler(struct ml_cpu_context *regs)
 
 	virt_addr_t fault_ptr = pf_faultptr();
 
+	ml_int_enable();
 	kern_status_t status = pmap_handle_fault(fault_ptr, fault_flags);
+	ml_int_disable();
 
 	if (status == KERN_OK) {
 		return;