x86, io_apic.c: Work around compiler warning

This compiler warning:

  arch/x86/kernel/apic/io_apic.c: In function ‘ioapic_write_entry’:
  arch/x86/kernel/apic/io_apic.c:466: warning: ‘eu’ is used uninitialized in this function
  arch/x86/kernel/apic/io_apic.c:465: note: ‘eu’ was declared here

Is bogus as 'eu' is always initialized. But annotate it away by
initializing the variable, to make it easier for people to notice
real warnings. A compiler that sees through this logic will
optimize away the initialization.
Signed-off-by: NFigo.zhang <figo1802@gmail.com>
LKML-Reference: <1245248720.3312.27.camel@myhost>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

arch/x86/kernel/apic/io_apic.c

@@ -462,7 +462,8 @@ static struct IO_APIC_route_entry ioapic_read_entry(int apic, int pin)
 static void
 __ioapic_write_entry(int apic, int pin, struct IO_APIC_route_entry e)
 {
-	union entry_union eu;
+	union entry_union eu = {{0, 0}};
+
 	eu.entry = e;
 	io_apic_write(apic, 0x11 + 2*pin, eu.w2);
 	io_apic_write(apic, 0x10 + 2*pin, eu.w1);