ARM: S3C64XX: Fix special function for IISv4 port

When converting to use s3c_gpio_cfgpin_range() the function for the
IISv4 block appears to have been typoed as 4 (the keypad) rather than
5 as it should be.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>