power: smb135x-charger: fix force_recharge debugfs property

The force_recharge should be a writeable property. Moreover if
charging is disabled it should respect that and not enable charging.
Fix it.

Change-Id: I978760f04f12a6a73dd12640cbc0aefbbaa6d25a
Signed-off-by: Abhijeet Dharmapurikar <adharmap@codeaurora.org>