genirq: Expand generic show_interrupts()

Some archs want to print extra information for certain irq_chips which
is per irq and not per chip. Allow them to provide a chip callback to
print the chip name and the extra information.

PowerPC wants to print the LEVEL/EDGE type information. Make it configurable.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/kernel/irq/Kconfig b/kernel/irq/Kconfig
index 09bef82..00f2c03 100644
--- a/kernel/irq/Kconfig
+++ b/kernel/irq/Kconfig
@@ -31,6 +31,10 @@
 config GENERIC_IRQ_SHOW
        bool
 
+# Print level/edge extra information
+config GENERIC_IRQ_SHOW_LEVEL
+       bool
+
 # Support for delayed migration from interrupt context
 config GENERIC_PENDING_IRQ
 	bool