ARM: dts: Add HS400 support for exynos5420 and exynos5800

HS400 timing values are added for SMDK5420, exynos5420-peach-pit
and exynos5800-peach-pi boards. This also adds RCLK GPIO line,
this gpio should be in pull-down state.
This also enables HS400 on peach-pi and this updates the clock
frequency to 800MHz to be set as input clock to controller.

Signed-off-by: Seungwon Jeon <tgih.jun@samsung.com>
[alim.akhtar@samsung.com: addressed review comments]
Signed-off-by: Alim Akhtar <alim.akhtar@samsung.com>
Acked-by: Jaehoon Chung <jh80.chung@samsung.com>
Signed-off-by: Kukjin Kim <kgene@kernel.org>