Clang warns:

../drivers/usb/dwc3/dwc3-meson-g12a.c:421:6: warning: variable 'ret' is
used uninitialized whenever 'if' condition is false
[-Wsometimes-uninitialized]
        if (priv->otg_mode == USB_DR_MODE_OTG) {
            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../drivers/usb/dwc3/dwc3-meson-g12a.c:455:9: note: uninitialized use
occurs here
        return ret;
               ^~~
../drivers/usb/dwc3/dwc3-meson-g12a.c:421:2: note: remove the 'if' if
its condition is always true
        if (priv->otg_mode == USB_DR_MODE_OTG) {
        ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../drivers/usb/dwc3/dwc3-meson-g12a.c:415:9: note: initialize the
variable 'ret' to silence this warning
        int ret, irq;
               ^
                = 0
1 warning generated.

It is not wrong, ret is only used when that if statement is true. Just
directly return 0 at the end to avoid this.

Fixes: 729149c53f04 ("usb: dwc3: Add Amlogic A1 DWC3 glue")
Reported-by: kbuild test robot <lkp@intel.com>
Link: https://groups.google.com/d/msg/clang-built-linux/w5iBENco_m4/PPuXreAxBQAJ
Link: https://github.com/ClangBuiltLinux/linux/issues/869Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Felipe Balbi <balbi@kernel.org>