r8152: adjust U2P3 for RTL8153

Use another way to keep disabling the U2P3 for both RTL_VER_03 and
RTL_VER_04.

Move enabling U2P3 from r8153_init() to r8153_hw_phy_cfg(). The
engineer ask the setting should be done after PHY settings.

Disable U2P3 first in rtl8153_up().

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