r8169: remove the media option

It has been documented as deprecated:
- in MODULE_PARM_DESC since may 2005 ;
- at the top of the source file and in printk since june 2004.

Good bye.

Signed-off-by: Francois Romieu <romieu@fr.zoreil.com>
Cc: Edward Hsu <edward_hsu@realtek.com.tw>