I2C: S3C24X0: Resolve build error for VCMA9

This patch resolves the following build errors for I2C driver in
VCMA9:

In file included from s3c24x0_i2c.c:40:0:
s3c24x0_i2c.h:38:17: error: field 'id' has incomplete type
s3c24x0_i2c.c:70:39: error: 'CONFIG_MAX_I2C_NUM' undeclared here (not
in a function) s3c24x0_i2c.c:70:31: warning: 'i2c_bus' defined but
not used [-Wunused-variable] s3c24x0_i2c.c:72:12: warning:
'i2c_busses' defined but not used [-Wunused-variable]

Signed-off-by: Rajeshwari Shinde <rajeshwari.s@samsung.com>
Signed-off-by: Minkyu Kang <mk7.kang@samsung.com>