ARM: dts: exynos: Move Exynos5420 bus related OPPs to the Odroid boards DTS

Currently the only Exynos5422-based boards that support bus frequency
scaling are Hardkernel's Odroid XU3/XU4/HC1. Move the bus related OPPs
to the boards DTS, because those OPPs heavily depend on the clock
topology and top PLL rates, which are being configured by the board's
bootloader.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Tested-by: Chanwoo Choi <cw00.choi@samsung.com>
Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>