staging: greybus: light: check the correct value of delay_on

When checking the value of delay_on to set the channel as active, it was
checked the pointer and not the value, as it should be.

Fixes: cc43368a

 ("greybus: lights: Control runtime pm suspend/resume on AP side")

Signed-off-by: Rui Miguel Silva <rmfrfs@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>