USB: bcma: drop Northstar PHY 2.0 initialization code

This driver should initialize controller only, PHY initialization should
be handled by separated PHY driver. We already have phy-bcm-ns-usb2 in
place so let it makes its duty.

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>