x86, apic: untangle the send_IPI_*() jungle

Our send_IPI_*() methods and definitions are a twisted mess: the same
symbol is defined to different things depending on .config details,
in a non-transparent way.

 - spread out the quirks into separately named per apic driver methods

 - prefix the standard PC methods with default_

 - get rid of wrapper macro obfuscation

 - clean up various details

Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/x86/kernel/apic.c b/arch/x86/kernel/apic.c
index 5f7f3a9..84b8e7c 100644
--- a/arch/x86/kernel/apic.c
+++ b/arch/x86/kernel/apic.c
@@ -475,7 +475,7 @@
 static void lapic_timer_broadcast(const struct cpumask *mask)
 {
 #ifdef CONFIG_SMP
-	send_IPI_mask(mask, LOCAL_TIMER_VECTOR);
+	apic->send_IPI_mask(mask, LOCAL_TIMER_VECTOR);
 #endif
 }