traps: x86: converge trap_init functions

- set_system_gate on i386 is really set_system_trap_gate
 - set_system_gate on x86_64 is really set_system_intr_gate
 - ist=0 means no special stack switch is done:
	- introduce STACKFAULT_STACK, DOUBLEFAULT_STACK, NMI_STACK,
		DEBUG_STACK and MCE_STACK as on x86_64.
	- use the _ist variants with XXX_STACK set to zero
 - remove set_system_gate

Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

traps: x86: correct copy/paste bug: a trap is a GATE_TRAP

Fix copy/paste/forgot-to-edit bug in desc.h.

Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/include/asm-x86/page_32.h b/include/asm-x86/page_32.h
index 5d6a68a..e8d80d1 100644
--- a/include/asm-x86/page_32.h
+++ b/include/asm-x86/page_32.h
@@ -20,6 +20,12 @@
 #endif
 #define THREAD_SIZE 	(PAGE_SIZE << THREAD_ORDER)
 
+#define STACKFAULT_STACK 0
+#define DOUBLEFAULT_STACK 1
+#define NMI_STACK 0
+#define DEBUG_STACK 0
+#define MCE_STACK 0
+#define N_EXCEPTION_STACKS 1
 
 #ifdef CONFIG_X86_PAE
 /* 44=32+12, the limit we can fit into an unsigned long pfn */