ARM: dts: Add Initial device tree support for odroidxu2

Add initial device tree for odroidxu2
ARM: odroidxu2_defconfig: odroidxu2 board based on exynos5420
 ARM: dts: odroid-xu2: Add heartbead and mmc LEDs support

 Add the support for LED1 on ODROID-XU2 board.
 -Red LED will be used for heartbeat
 -Green LED will be used for eMMC
 -Blue LED will be used for microSD
ARM: Add Kconfig to 16 of NR_BANKS for EXYNOS5420