misc: isl29020: add missed pm_runtime_disable

The driver forgets to call pm_runtime_disable in remove.
Add the missed call to fix it.

Signed-off-by: Chuhong Yuan <hslester96@gmail.com>
Link: https://lore.kernel.org/r/20191118080931.30749-1-hslester96@gmail.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>