r8152: remove rtl_phy_reset function

In rtl_hw_phy_work_func_t(), the flag of PHY_RESET is set in
rtl_ops.hw_phy_cfg() and cleared in rtl8152_set_speed(). Therefore,
the rtl_phy_reset() is never run and is unnecessary.

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