ARM: s3c24xx: convert to sparse-irq

As a final bit of preparation for converting to ARCH_MULTIPLATFORM,
change the interrupt handling for s3c24xx to use sparse IRQs.

Since the number of possible interrupts is already fixed and relatively
small per chip, just make it use all legacy interrupts preallocated
using the .nr_irqs field in the machine descriptor, rather than actually
allocating domains on the fly.

Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

ARM: s3c: make headers local if possible

A lot of header files are only used internally now, so they can be moved
to mach-s3c, out of the visibility of drivers.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20200806182059.2431-40-krzk@kernel.org
[krzk: Rebase and fixup leds-s3c24xx driver]
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>

ARM: s3c: move into a common directory

s3c24xx and s3c64xx have a lot in common, but are split across three
separate directories, which makes the interaction of the header files
more complicated than necessary.

Move all three directories into a new mach-s3c, with a minimal
set of changes to each file.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
[krzk: Rebase, add s3c24xx and s3c64xx suffix to several files, add SPDX
headers to new files, remove plat-samsung from MAINTAINERS]
Co-developed-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
https://lore.kernel.org/r/20200806182059.2431-39-krzk@kernel.org