ARM: S3C24XX: make gta02.h local

The header can be local in mach-s3c24xx/ and sort out inclusions.
Accordingly, the GTA02_ macro in driver can be replaced.

Cc: Sangbeom Kim <sbkim73@samsung.com>
Cc: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>