drivers: gadget: rockusb: Fix rkusb_do_vs read/write support

rockusb vs r/w no need depends on vendor storage. It already
supports many other paths to store secure data.

Change-Id: I4b47227fb00978082c57b1af4c96c63d12c51ed7
Signed-off-by: Xuhui Lin <xuhui.lin@rock-chips.com>