xen/arm: gic-hip04: Resync the driver with the GICv2

xen/arm: gic-hip04: Resync the driver with the GICv2

The GIC hip04 driver was differring from GICv2. I suspect that some of
the changes in the common GIC code make boot fail on hip04. Although, I
don't have a platform to check so it has been only build tested.

List of GICv2 commit ported to the HIP04:
    commit ce12e6dba4b2d120e35dffd95a745452224e7144
    Author: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
    Date:   Fri Apr 10 16:21:10 2015 +1000

        xen/arm: Don't write to GICH_MISR

        GICH_MISR is read-only in GICv2.

        Signed-off-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
        Reviewed-by: Julien Grall <julien.grall@citrix.com>
        Acked-by: Ian Campbell <ian.campbell@citrix.com>
    commit 2eb4f996547dc632aa94b2b7b4f783bec8ffe457
    Author: Julien Grall <julien.grall@linaro.org>
    Date:   Wed Apr 1 17:21:47 2015 +0100

        xen/arm: gic: GICv2 & GICv3 only supports 1020 physical interrupts

        GICD_TYPER.ITLinesNumber can encode up to 1024 interrupts. Although,
        IRQ 1020-1023 are reserved for special purpose.

        The result is used by the callers of gic_number_lines in order to check
        the validity of an IRQ.

        Signed-off-by: Julien Grall <julien.grall@linaro.org>
        Acked-by: Ian Campbell <ian.campbell@citrix.com>
        Cc: Frediano Ziglio <frediano.ziglio@huawei.com>
        Cc: Zoltan Kiss <zoltan.kiss@huawei.com>
    commit e2d486b385ce58b6db7561417de28ba837dcd4ac
    Author: Julien Grall <julien.grall@linaro.org>
    Date:   Wed Apr 1 17:21:34 2015 +0100

        xen/arm: Divide GIC initialization in 2 parts

        Currently the function to translate IRQ from the device tree is set
        unconditionally  to be able to be able to retrieve serial/timer IRQ
        before the GIC has been initialized.

        It assumes that the xlate function won't ever changed. We may also need
        to have the primary interrupt controller very early.

        Rework the gic initialization in 2 parts:
            - gic_preinit: Get the interrupt controller device tree node and
            set up GIC and xlate callbacks
            - gic_init: Initialize the interrupt controller and the boot CPU
            interrupts.

        The former function will be called just after the IRQ subsystem as been
        initialized.

        Signed-off-by: Julien Grall <julien.grall@linaro.org>
        Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
        Acked-by: Ian Campbell <ian.campbell@citrix.com>
        Cc: Frediano Ziglio <frediano.ziglio@huawei.com>
        Cc: Zoltan Kiss <zoltan.kiss@huawei.com>
Signed-off-by: Julien Grall <julien.grall@citrix.com>
Cc: Zoltan Kiss <zoltan.kiss@huawei.com>
Reviewed-by: Zoltan Kiss <zoltan.kiss@huawei.com>
Tested-by: Shameerali Kolothum Thodi <shameerali.kolothum.thodi@huawei.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>