ARM: dts: imx6qdl: SolidRun: add v1.5 som with eMMC

Add Cubox-i and Hummingboard variants for v1.5 SOMs, where the SOM has
eMMC fitted.

Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Reviewed-by: Fabio Estevam <fabio.estevam@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>