usb: dwc3: qcom: Fix error handling in probe

There are two issues:
1) Return -EINVAL if platform_get_resource() fails.  Don't return
   success.
2) The devm_ioremap() function doesn't return error pointers, it returns
   NULL.  Update the check.

Fixes: 1881a32f ("usb: dwc3: qcom: Transition to flattened model")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Bjorn Andersson <andersson@kernel.org>
Acked-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Link: https://lore.kernel.org/r/aAijmfAph0FlTqg6@stanley.mountain


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>