[PATCH 5/6] i2c: exynos5: Add bus clock support

[Chanho Park]

> In new Exynos SoCs (like Exynos850) where HSI2C is implemented as a part
> of USIv2 block, there are two clocks provided to HSI2C controller:
>   - PCLK: bus clock (APB), provides access to register interface
>   - IPCLK: operating IP-core clock; SCL is derived from this one
> 
> Both clocks have to be asserted for HSI2C to be functional in that case.
> 
> Add code to obtain and enable/disable PCLK in addition to already handled
> operating clock. Make it optional though, as older Exynos SoC variants
> only have one HSI2C clock.
> 
> Signed-off-by: Sam Protsenko <semen.protsenko at linaro.org>

Reviewed-by: Chanho Park <chanho61.park at samsung.com>

Best Regards,
Chanho Park