[ARM] 5395/1: RealView: Add support for the DS1338 RTC chip

This chip is on the I2C bus on the RealView and Versatile boards. The
patch adds the i2c_board_info definition for this device and registers
it with the I2C subsystem.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>