In gsi_channel_setup(), we check to see if the configuration data
contains any information about channels that are not supported by
the hardware.  If one is found, we abort the setup process, but
the error code (ret) is not set in this case.  Fix this bug.

Fixes: 650d1603 ("soc: qcom: ipa: the generic software interface")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Alex Elder <elder@linaro.org>
Link: https://lore.kernel.org/r/20210204010655.15619-1-elder@linaro.orgSigned-off-by: Jakub Kicinski <kuba@kernel.org>