i2c: add deprecation warning for class based instantiation

Class based instantiation can cause noticeable delays when booting. This
mechanism is used when it is not possible to describe slaves on I2C
busses. As we do have other mechanisms, most embedded I2C will not need
classes and for embedded it is explicitly not recommended to use them. Add
a deprecation warning for drivers which want to disable class based
instantiation in the near future to gain boot-up time, so users relying
on this technique can switch to something better. They really should.

Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
irqchip: sun4i: Don't ack IRQs > 0, fix acking of IRQ 0

All IRQs except for IRQ 0 seem to not need acking, so drop acking for them.

The ENMI needs to have the ack done *after* clearing the interrupt source,
otherwise we will get a spurious interrupt for each real interrupt.

So use the new IRQCHIP_EOI_THREADED flag for this in combination with
handle_fasteoi_irq. This uses a separate irq_chip struct for IRQ 0,
since we only want this behavior for IRQ 0.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-sunxi@googlegroups.com
Cc: Maxime Ripard <maxime.ripard@free-electrons.com>
Link: http://lkml.kernel.org/r/1394733834-26839-5-git-send-email-hdegoede@redhat.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

Conflicts:
	drivers/irqchip/irq-sun4i.c