powerpc/mpc85xx: add MPIC message dts node

Signed-off-by: Mingkai Hu <Mingkai.hu@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>

powerpc/mpic: Add "last-interrupt-source" property to override hardware

The FreeScale PowerQUICC-III-compatible (mpc85xx/mpc86xx) MPICs do not
correctly report the number of hardware interrupt sources, so software
needs to override the detected value with "256".

To avoid needing to write custom board-specific code to detect that
scenario, allow it to be easily overridden in the device-tree.

Signed-off-by: Kyle Moffett <Kyle.D.Moffett@boeing.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

fsl/mpic: Create and document the "single-cpu-affinity" device-tree flag

The Freescale MPIC (and perhaps others in the future) is incapable of
routing non-IPI interrupts to more than once CPU at a time. Currently
all of the Freescale boards msut pass the MPIC_SINGLE_DEST_CPU flag to
mpic_alloc(), but that information should really be present in the
device-tree.

Older board code can't rely on the device-tree having the property set,
but newer platforms won't need it manually specified in the code.

[BenH: Remove unrelated changes, folded in a different patch]

Signed-off-by: Kyle Moffett <Kyle.D.Moffett@boeing.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

fsl/mpic: Document and use the "big-endian" device-tree flag

The MPIC code checks for a "big-endian" property and sets the flag
MPIC_BIG_ENDIAN if one is present, although prior to the "mpic->flags"
fixup that would never have worked anways.

Unfortunately, even now that it works properly, the Freescale mpic
device-node (the "PowerQUICC-III"-compatible one) does not specify it,
so all of the board ports need to manually pass it to mpic_alloc().

Document the flag and add it to the pq3 device tree. Existing code will
still need to pass the MPIC_BIG_ENDIAN flag because their dtb may not
have this property, but new platforms shouldn't need to do so.

Signed-off-by: Kyle Moffett <Kyle.D.Moffett@boeing.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

powerpc/85xx: create dts components to build up an SoC

Introduce some common components that we can utilize to build up the
various PQ3/85xx device trees.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>