r8169: wake up the PHY of the 8168

This is typically needed when some other OS puts the PHY
to sleep due to the disabling of WOL options in the BIOS
of the system.

Signed-off-by: Francois Romieu <romieu@fr.zoreil.com>
Tested-by: Chiaki Ishikawa <chiaki.ishikawa@ubin.jp>
Cc: Edward Hsu <edward_hsu@realtek.com.tw>
Cc: RyanKao <ryankao@realtek.com.tw>