ARM: S3C24XX: Fix mess with gpio {set,get}_pull callbacks

Currently the {set,get}_pull callbacks of the s3c24xx_gpiocfg_default structure
are initalized via s3c_gpio_{get,set}pull_1up. This results in a linker
error when only CONFIG_CPU_S3C2442 is selected:

arch/arm/plat-s3c24xx/built-in.o:(.data+0x13f4): undefined reference to
`s3c_gpio_getpull_1up'
arch/arm/plat-s3c24xx/built-in.o:(.data+0x13f8): undefined reference to
`s3c_gpio_setpull_1up'

The s3c2442 has pulldowns instead of pullups compared to the s3c2440.
The method of controlling them is the same though.
So this patch modifies the existing s3c_gpio_{get,set}pull_1up helper functions
to take an additional parameter deciding whether the pin has a pullup or pulldown.
The s3c_gpio_{get,set}pull_1{down,up} functions then wrap that functions passing
either S3C_GPIO_PULL_UP or S3C_GPIO_PULL_DOWN.

Furthermore this patch sets up the s3c24xx_gpiocfg_default.{get,set}_pull fields
in the s3c244{0,2}_map_io function to the new pulldown helper functions.

Based on patch from "Lars-Peter Clausen" <lars@metafoo.de>

Signed-off-by: Vasily Khoruzhick <anarsoul@gmail.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>