[POWERPC] Make cpus_in_xmon static and remove extern mess from hvc_console.c

This is a little messier than I'd like because xmon.h only exists
on powerpc and we can't have a static inline and an extern declaration
visible at the same time.

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c
index 95f24c9..6726da0 100644
--- a/arch/powerpc/xmon/xmon.c
+++ b/arch/powerpc/xmon/xmon.c
@@ -54,7 +54,7 @@
 #define skipbl	xmon_skipbl
 
 #ifdef CONFIG_SMP
-cpumask_t cpus_in_xmon = CPU_MASK_NONE;
+static cpumask_t cpus_in_xmon = CPU_MASK_NONE;
 static unsigned long xmon_taken = 1;
 static int xmon_owner;
 static int xmon_gate;
@@ -327,6 +327,11 @@
 {
 	xmon_speaker = 0;
 }
+
+int cpus_are_in_xmon(void)
+{
+	return !cpus_empty(cpus_in_xmon);
+}
 #endif
 
 static int xmon_core(struct pt_regs *regs, int fromipi)