dt-bindings: clock: Add I2C, HSI2C and RTC clock IDs to Exynos5410

Add IDs for I2C, USI (HSI2C) and RTC clocks to Exynos5410. Use the same
number as for Exynos5420 just in case in future these drivers are merged.

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Reviewed-by: Javier Martinez Canillas <javier@osg.samsung.com>
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>