lantiq: Add usb initialization bits from ltq-hcd to platform init

Add VR9 specific usb initialization bits from ltq-hcd to platform
initialization.

This patch is more of a proof-of-concept than production quality
since the initialization registers are different on other lantiq
platforms.

Signed-off-by: Antti Seppälä <a.seppala@gmail.com>
Signed-off-by: Vincent Pelletier <plr.vincent@gmail.com>

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@44672 3c298f89-4303-0410-b956-a3cf2f4a3e73