ralink: fix mt7620 ohci 3.10

the ohci phy was not reset properly

Signed-off-by: John Crispin <blogic@openwrt.org>

Backport of r42290

git-svn-id: svn://svn.openwrt.org/openwrt/branches/barrier_breaker@42384 3c298f89-4303-0410-b956-a3cf2f4a3e73