net: stmmac: dwmac-qcom-ethqos: Drop an if with an always false condition

The remove callback is only ever called after .probe() returned
successfully. After that get_stmmac_bsp_priv() always return non-NULL.

Side note: The early exit would also be a bug because the return value
of qcom_ethqos_remove() is ignored by the device core and the device is
unbound unconditionally. So exiting early resulted in a dangerous
resource leak as all devm allocated resources (some memory and the
register mappings) are freed but the network device stays around.  Using
the network device afterwards probably oopses.

Reviewed-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Michal Kubiak <michal.kubiak@intel.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>