x86/nmi: Drop K7_NMI_EVENT

This name is misleading.

It's not possible to configure NMI or not from the event select register; that
comes from the APIC configuration for performance events.

This name is "the thing we want to count for the NMI watchdog", but that's
clearer to follow when it simply names the event.  Drop the indirection.

No functional change.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Jan Beulich <jbeulich@suse.com>

xen/arch/x86/nmi.c

@@ -102,7 +102,6 @@ static int nmi_active;
 #define K7_EVNTSEL_OS		(1 << 17)
 #define K7_EVNTSEL_USR		(1 << 16)
 #define K7_EVENT_CYCLES_PROCESSOR_IS_RUNNING	0x76
-#define K7_NMI_EVENT		K7_EVENT_CYCLES_PROCESSOR_IS_RUNNING
 #define K7_EVENT_WIDTH          32
 
 #define P6_EVNTSEL0_ENABLE	(1 << 22)
@@ -259,7 +258,7 @@ static void setup_k7_watchdog(void)
     evntsel = K7_EVNTSEL_INT
         | K7_EVNTSEL_OS
         | K7_EVNTSEL_USR
-        | K7_NMI_EVENT;
+        | K7_EVENT_CYCLES_PROCESSOR_IS_RUNNING;
 
     wrmsrns(MSR_K7_EVNTSEL0, evntsel);
     write_watchdog_counter("K7_PERFCTR0");