Add support for enabling the clock security system, which can detect
failures of the HSE clock.
Includes tests for nucleo_h743zi and nucleo_g474re.
Signed-off-by: Kevin ORourke <kevin.orourke@ferroamp.se>
DTS property attributes are (by default) not required.
Explicitly specifying `required: false` is redundant.
Perhaps a warning to that effect would be useful.
Signed-off-by: Chris Friedt <cfriedt@meta.com>
Kevin ORourke