x86/apic/flat64: Remove the IPI shorthand decision logic

All callers of apic->send_IPI_all() and apic->send_IPI_allbutself() contain
the decision logic for shorthand invocation already and invoke
send_IPI_mask() if the prereqisites are not satisfied.

Remove the now redundant decision logic in the APIC code and the duplicate
helper in probe_64.c.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20190722105221.042964120@linutronix.de

arch/x86/kernel/apic/probe_64.c

@@ -36,13 +36,6 @@ void __init default_setup_apic_routing(void)
 		x86_platform.apic_post_init();
 }
 
-/* Same for both flat and physical. */
-
-void apic_send_IPI_self(int vector)
-{
-	__default_send_IPI_shortcut(APIC_DEST_SELF, vector);
-}
-
 int __init default_acpi_madt_oem_check(char *oem_id, char *oem_table_id)
 {
 	struct apic **drv;