ramips: awake rt305x USB controller

Because of Ralink uboot set USB controller into sleep mode [1]
we check it and awake controller before any registers access.
Fix ticket #21396 [2]

[1] http://marc.info/?l=linux-usb&m=137398626102108&w=2
[2] https://dev.openwrt.org/ticket/21396



Signed-Off-By: Serge Vasilugin <vasilugin@yandex.ru>

SVN-Revision: 49212