usb: misc: ehset: fix wrong if condition

A negative number from ret means the host controller had failed to send
usb message and 0 means succeed. Therefore, the if logic is wrong here
and this patch will fix it.

Fixes: f2b42379 ("usb: misc: ehset: Rework test mode entry")
Cc: stable <stable@kernel.org>
Signed-off-by: Xu Yang <xu.yang_2@nxp.com>
Link: https://lore.kernel.org/r/20230705095231.457860-1-xu.yang_2@nxp.com


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