x86: move _set_gate and its users to a common location

This patch moves _set_gate and its users to desc.h. We can now
use common code for x86_64 and i386.

[ mingo@elte.hu: set_system_gate() fixes for nasty crashes. ]

Signed-off-by: Glauber de Oliveira Costa <gcosta@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/include/asm-x86/desc_defs.h b/include/asm-x86/desc_defs.h
index ebb64fe..e33f078 100644
--- a/include/asm-x86/desc_defs.h
+++ b/include/asm-x86/desc_defs.h
@@ -36,6 +36,7 @@
 	GATE_INTERRUPT = 0xE,
 	GATE_TRAP = 0xF,
 	GATE_CALL = 0xC,
+	GATE_TASK = 0x5,
 };
 
 // 16byte gate
@@ -55,10 +56,6 @@
 enum {
 	DESC_TSS = 0x9,
 	DESC_LDT = 0x2,
-	DESCTYPE_TASK = 0x85,   /* present, system, DPL-0, task gate */
-	DESCTYPE_INT =  0x8e,   /* present, system, DPL-0, interrupt gate */
-	DESCTYPE_TRAP = 0x8f,   /* present, system, DPL-0, trap gate */
-	DESCTYPE_DPL3 = 0x60,   /* DPL-3 */
 	DESCTYPE_S =	0x10,	/* !system */
 };