ARM: dts: stm32: Update red led node for stm32mp157c-ed1-u-boot

ARM: dts: stm32: Update red led node for stm32mp157c-ed1-u-boot

As indicated in kernel led dt-bindings, label is a deprecated
property, so remove it and use led node's name instead for
u-boot,error-led property.
Rename red led node's name to led-red.
Remove status property which is useless.
Add compatible = "gpio-leds" which is not present in kernel DT.

Signed-off-by: Patrice Chotard <patrice.chotard@foss.st.com>
Reviewed-by: Patrick Delaunay <patrick.delaunay@foss.st.com>