ARM: dts: imx27-phytec-phycore: Add diagnostic PMIC LEDs

PCM-038 module have three triple LEDs connected to PMIC which
can be used for diagnostic purposes. This patch adds support
for these LEDs for PCM-038 SOM and adds basic LED-triggers for
these LEDs for PCM-970 RDK, the remaining LEDs are available
for use from userspace.

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>