staging: greybus: pwm: Drop unused gb_connection_set_data()

staging: greybus: pwm: Drop unused gb_connection_set_data()

The driver never calls gb_connection_get_data(). If there was another
caller (say the greybus core) it cannot use the value because the type
of pwmc (= struct gb_pwm_chip) is only defined in the pwm driver.

So drop the call to gb_connection_set_data().

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/bd2759c325c295f3d9f990609d97eb83a8ca88b8.1707900770.git.u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>