stm32mp: stm32prog: reactivate console and display serial error

When serial instance is not found in device tree, the console
should be enabled and the error should be indicated.

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