ARM: dts: imx6qdl: SolidRun: fix node names

Node names are supposed to be generic, fix the RTC and codec node
names for both Hummingboard and Cubox-i.

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>