gpio/pca953x: Fix warning of enabled interrupts in handler

gpio/pca953x: Fix warning of enabled interrupts in handler

commit 6dd599f8af0166805951f4421a78ba716d78321a upstream.

When using nested threaded irqs, use handle_nested_irq(). This function
does not call the chip handler, so no handler is set.

Signed-off-by: David Jander <david@protonic.nl>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Yong Zhang <yong.zhang0@gmail.com>
Cc: Manfred Gruber <m.gruber@unverspurt.at>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>