Add IRQC interrupt controller support to r8a7790 by
hooking up a single IRQC instances to handle 4 external
IRQ signals. The IRQC controller is tied to SPIs of
the GIC. On r8a7790 the external IRQ pins routing is
handled by the PFC which is excluded from this patch.

Both platform devices and DT devices are added in this
patch. The platform device versions are used to provide
a static interrupt map configuration for board code
written in C.
Signed-off-by: NMagnus Damm <damm@opensource.se>
Signed-off-by: NSimon Horman <horms+renesas@verge.net.au>

Add SCIF serial port support to the r8a7790 SoC by
adding platform devices for SCIFA0 -> SCIFA2 as well
as SCIFB0 -> SCIFB2 and SCIF0 -> SCIF1 together with
clock bindings. DT device description is excluded at
this point since such bindings are still under
development.
Signed-off-by: NMagnus Damm <damm@opensource.se>
Signed-off-by: NSimon Horman <horms+renesas@verge.net.au>

Add initial support for the r8a7790 SoC including:
 - Single Cortex-A15 CPU Core
 - GIC
 - Architecture timer

No static virtual mappings are used, all the components
make use of ioremap(). DT_MACHINE_START is still wrapped
in CONFIG_USE_OF to match other mach-shmobile code.
Signed-off-by: NMagnus Damm <damm@opensource.se>
Signed-off-by: NSimon Horman <horms+renesas@verge.net.au>