The BAREBOX_CMD_HELP_OPT macro adds a newline to the string, but users
of the macro inconsistently add another newline resulting in empty
newlines for some commands, but not for others. Remove any newline in
the description and rely on BAREBOX_CMD_HELP_OPT for the formatting.

Signed-off-by: Michael Tretter <m.tretter@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>