The NXP LPC syscon driver failed to build on several platforms for
various reasons. We need dts support on LPC55s1x and LPC55s2x, the
driver doesn't seem like it will work on LPC54114 so we exclude it
there for now.
Additionally, fix a dtc warning on LPC55s6x based on unit-address in
the node naming needing to be lowercase.
Signed-off-by: Kumar Gala <kumar.gala@linaro.org>