ARM: dts: enable SPI1 for exynos4412-odroidu3

SPI1 is available on IO Port #2 (as depicted on their website)
in PCB Revision 0.5 of Hardkernel Odroid U3 board.
The shield connects a 256KiB spi-nor flash on that bus.

Signed-off-by: Alexis Ballier <aballier@gentoo.org>
Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Kukjin Kim <kgene@kernel.org>