ARM: gemini: DT for the Cortina Gemini SoC platforms
This adds initial and compulsory device tree support to the
Gemini ARMv4 platform.
We are selecting a bunch of "absolute minimals" for getting a working
system up with just device tree:
- We select USE_OF for natural reasons or nothing works.
- We select CLKSRC_OF and GEMINI_TIMER so we get timekeeping from
the clocksource.
- We select GPIO_GEMINI because these are used as irqchips, and
for a generic driver it is not reasonable for those to have to
select every possible irqchip in the world to work, the platform
should simply provide the available irqchips.
- We select a UART that can be exprected to work with
SERIAL_OF_PLATFORM which is the name for an 8250 OF-probed
serial port.
- We select the syscon-based reset controller: it's not fun when
"reboot" doesn't work because of Kconfig, so we just select
POWER_RESET and POWER_RESET_SYSCON.
- We perhaps a bit controversiallt select ARM_APPENDED_DTB, because
this platform is using the ancient RedBoot, and can *NOT* be
expected to upgrade its bootloaders. Appended device tree is
simply how these devices have to work with device tree.