r8152: move the setting for the default speed

Move calling set_speed() from open() to rtl_hw_phy_work_func_t().
Then, we would set the default speed only for first initialization
or after resuming.

Besides, the set_speed() could handle the flag of PHY_RESET which
would be set in rtl_ops.hw_phy_cfg().

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