rtl818x: Move configuration details to the rtl818x directory

In preparation for new rtl818x devices, move the existing rtl818x configuration
into the rtl818x directory.

Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Acked-by: Hin-Tak Leung <htl10@users.sourceforge.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>