ARM: s3c: enable s3c24xx multiplatform support

With the custom ISA I/O and the missing sparse-irq support
out of the way, s3c24xx can now be built into the same
kernel as all other ARM9 based platforms.

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