scripts/yocto-bsp: Exit successfully when asking for help

When user asks for help, the command should not exit with non-zero
status (failure), so removing the non-zero value on the system exit call.

(From meta-yocto rev: 98970326fb2f08e684cfc856103b2f9110c9f4fb)

Signed-off-by: Leonardo Sandoval <leonardo.sandoval.gonzalez@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

scripts/yocto-bsp

@@ -140,7 +140,7 @@ def main():
         if args[0] == "help":
             if len(args) == 1:
                 parser.print_help()
-                sys.exit(1)
+                sys.exit()
 
     invoke_subcommand(args, parser, yocto_bsp_help_usage, subcommands)