runners: jlink: exit with error in case of a failure

Add "ExitOnError 1" argument that treats any command-error
as fatal thus in the case of a programming error the "west flash"
command will return the correct error code instead of the default 0. It
fixes the false positive return codes when e.g we call west flash
command without a connected programmer or with the disconnected board.

Signed-off-by: Bartosz Bilas <b.bilas@grinn-global.com>
1 file changed