genirq: Implement generic irq_show_interrupts()

All archs implement show_interrupts() in more or less the same
way. That's tons of duplicated code with different bugs with no
value. Implement a generic version and deprecate show_interrupts()

Unfortunately we need some ifdeffery for !GENERIC_HARDIRQ archs.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/kernel/irq/Kconfig b/kernel/irq/Kconfig
index 8e42fec..4cd5d71 100644
--- a/kernel/irq/Kconfig
+++ b/kernel/irq/Kconfig
@@ -20,6 +20,9 @@
 config GENERIC_IRQ_PROBE
 	def_bool n
 
+config GENERIC_IRQ_SHOW
+       def_bool n
+
 config GENERIC_PENDING_IRQ
 	def_bool n