Merge irq-pxa168 and irq-mmp2. And support device tree also.

Since CONFIG_SPARSE_IRQ is enabled in arch-mmp, base irq starts from
NR_IRQS_LEGACY.
Signed-off-by: NHaojian Zhuang <haojian.zhuang@gmail.com>
Acked-by: NArnd Bergmann <arnd@arndb.de>

Now that most platforms don't need disable_fiq and arch_ret_to_user
macros, we can remove the empty macros or empty entry-macro.S files.
Signed-off-by: NRob Herring <rob.herring@calxeda.com>
Acked-by: NJamie Iles <jamie@jamieiles.com>
Acked-by: NNicolas Pitre <nico@linaro.org>
Acked-by: NTony Lindgren <tony@atomide.com>
Acked-by: NLinus Walleij <linus.walleij@linaro.org>
Acked-by: NRyan Mallon <rmallon@gmail.com>
Acked-by: NNicolas Ferre <nicolas.ferre@atmel.com>
Acked-by: NH Hartley Sweeten <hsweeten@visionengravers.com>
Acked-by: NShawn Guo <shawn.guo@linaro.org>

Marvell MMP2 (aka ARMADA610) is a SoC based on PJ4 core. It's
ARMv6 compatible.  Support basic interrupt handler and timer,
and basic support for MMP2 based FLINT platform.
Signed-off-by: NHaojian Zhuang <haojian.zhuang@marvell.com>
Signed-off-by: NEric Miao <eric.y.miao@gmail.com>

"""The Marvell® PXA168 processor is the first in a family of application
processors targeted at mass market opportunities in computing and consumer
devices. It balances high computing and multimedia performance with low
power consumption to support extended battery life, and includes a wealth
of integrated peripherals to reduce overall BOM cost .... """

See http://www.marvell.com/featured/pxa168.jsp for more information.

  1. Marvell Mohawk core is a hybrid of xscale3 and its own ARM core,
     there are many enhancements like instructions for flushing the
     whole D-cache, and so on

  2. Clock reuses Russell's common clkdev, and added the basic support
     for UART1/2.

  3. Devices are a bit different from the 'mach-pxa' way, the platform
     devices are now dynamically allocated only when necessary (i.e.
     when pxa_register_device() is called). Description for each device
     are stored in an array of 'struct pxa_device_desc'. Now that:

     a. this array of device description is marked with __initdata and
        can be freed up system is fully up

     b. which means board code has to add all needed devices early in
        his initializing function

     c. platform specific data can now be marked as __initdata since
        they are allocated and copied by platform_device_add_data()

  4. only the basic UART1/2/3 are added, more devices will come later.
Signed-off-by: NJason Chagas <chagas@marvell.com>
Signed-off-by: NEric Miao <eric.miao@marvell.com>