debug: coredump: flash backend: print error if write fails

The loop in `coredump_flash_backend_buffer_output` might fail without
any alerts. This could be due to e.g. a too small coredump-partion.

Add a LOG_ERR if an error occurs.

Signed-off-by: Jeppe Odgaard <jeppe.odgaard@prevas.dk>
1 file changed