USB: f81232: remove bogus call to wake up MSR queue

Remove bogus call to wake up delta_msr_wait from process_read_urb where
the MSR status is never updated (only the LSR bits are masked out).

Comment that the wake-up call should made in f81232_update_line_status
when the MSR status changes.

Note that this driver is still mostly stubbed out.

Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>