i2c: pnx: Fix potential deadlock warning from del_timer_sync() call in isr

In the Linux kernel, the following vulnerability has been resolved: i2c: pnx: Fix potential deadlock warning from del_timer_sync() call in isr When del_timer_sync() is called in an interrupt context it throws a warning because of potential deadlock. The timer is used only to exit from wait_for_completion() after a timeout so replacing the call with wait_for_completion_timeout() allows to remove the problematic timer and its related functions altogether.