Input: pegasus_notetaker - fix usb_autopm calls to be balanced

We should only "put" the interface if submitting URB or setting tablet mode
in pegasus_open() fails, otherwise leave it to pegasus_close().

Signed-off-by: Martin Kepplinger <martink@posteo.de>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>