xen: clean up gate trap/interrupt constants

Use GATE_INTERRUPT/TRAP rather than 0xe/f.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index 80f4c53..12a3159 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -428,7 +428,7 @@
 static int cvt_gate_to_trap(int vector, const gate_desc *val,
 			    struct trap_info *info)
 {
-	if (val->type != 0xf && val->type != 0xe)
+	if (val->type != GATE_TRAP && val->type != GATE_INTERRUPT)
 		return 0;
 
 	info->vector = vector;
@@ -436,8 +436,8 @@
 	info->cs = gate_segment(*val);
 	info->flags = val->dpl;
 	/* interrupt gates clear IF */
-	if (val->type == 0xe)
-		info->flags |= 4;
+	if (val->type == GATE_INTERRUPT)
+		info->flags |= 1 << 2;
 
 	return 1;
 }