qcom-charger: smb-lib: correct the usb suspend votable name

Currently the name of the votable that suspends usb is INPUT_SUSPEND.
However, the PMI has two inputs - USB and DC. The dc suspending votable
is correctly named DC_SUSPEND. So rename the INPUT_SUSPEND to an
appropriate name - USB_SUSPEND.

Change-Id: Ia5ea1b139f5e9d560dc6492aa9fc13ffeeda83ca
Signed-off-by: Abhijeet Dharmapurikar <adharmap@codeaurora.org>