odroid: add board file for Odroid X2/U3 based on Samsung Exynos4412

odroid: add board file for Odroid X2/U3 based on Samsung Exynos4412

This board file supports standard features of Odroid X2 and U3 boards:
- Exynos4412 core clock set to 1000MHz and MPLL peripherial clock set to 800MHz,
- MAX77686 power regulator,
- USB PHY,
- enable XCL205 - power for board peripherials
- check board type: U3 or X2.
- enable Odroid U3 FAN cooler

Signed-off-by: Przemyslaw Marczak <p.marczak@samsung.com>
Cc: Minkyu Kang <mk7.kang@samsung.com>
Cc: Tom Rini <trini@ti.com>
Signed-off-by: Minkyu Kang <mk7.kang@samsung.com>