arm64: dts: layerscape: add ftm_alarm0 node

The patch adds ftm_alarm0 DT node
	- add new rcpm node
	- add ftm_alarm0 node
	- aliases ftm_alarm0 as rtc1

Signed-off-by: Biwen Li <biwen.li@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>