r8152: remove clearing bp

The xxx_clear_bp() is used to halt the firmware. It only necessary
for updating the new firmware. Besides, depend on the version of
the current firmware, it may have problem to halt the firmware
directly. Finally, halt the firmware would let the firmware code
useless, and the bugs which are fixed by the firmware would occur.

Signed-off-by: Hayes Wang <hayeswang@realtek.com>
Signed-off-by: David S. Miller <davem@davemloft.net>