usb: dwc2: fix sparse warning

Sparse warns about the __le16 wValue from the USB SetAddress
command being used without converting it to CPU endianness. Fix
that, and also add a bit of defensive masking of the received
wValue before using it.

Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Paul Zimmerman <paulz@synopsys.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>