ARM: s3c: simplify s3c_irqwake_{e,}intallow definition

For a long time, gcc has warned about odd configurations on s3c64xx:

In file included from arch/arm/plat-samsung/pm.c:34:0:
arch/arm/mach-s3c64xx/include/mach/pm-core.h:61:0: warning: "s3c_irqwake_eintallow" redefined
 #define s3c_irqwake_eintallow ((1 << 28) - 1)
In file included from arch/arm/plat-samsung/pm.c:33:0:
arch/arm/plat-samsung/include/plat/pm.h:49:0: note: this is the location of the previous definition
 #define s3c_irqwake_eintallow 0

The definitions of s3c_irqwake_intallow and s3c_irqwake_eintallow are a
bit consistent between the various platforms. Things have become easier
now that it's only s3c24xx and s3c64xx that use them at all, so I've tried
to rearrange the definitions to make it more obvious what is going on.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>