r8152: move the settings of PHY to a work queue

Move the settings of PHY to a work queue and schedule it after
rtl_ops.init().

There are some reasons for this. First, the settings are only
needed for the first time initialization or after the power
down occurs.

Second, the settings are independent with the others.

Last, the settings may take more time than the others. Leave
they in probe() or open() may delay the following flows.

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