1. Changed return value of function: shell_cmd_precheck from bool to
int. Now it returns:
0 when argument count is correct and help print is not requested
1 when help was requested and printed
-EINVAL on wrong arguments count
This change simply shell_cmd_precheck usege in command handlers.
2. Unified all commands in shell_cmd.c file.
3. Fixed a bug where help was not printed on wrong argument count.
Signed-off-by: Jakub Rzeszutko <jakub.rzeszutko@nordicsemi.no>
1. Command handler can return command exectution status as int.
2. Existing command handlers rework.
Signed-off-by: Jakub Rzeszutko <jakub.rzeszutko@nordicsemi.no>
