PCI: iproc: Convert to platform remove callback returning void

PCI: iproc: Convert to platform remove callback returning void

The .remove() callback for a platform driver returns an int which makes
many driver authors wrongly assume it's possible to do error handling by
returning an error code. However the value returned is (mostly) ignored
and this typically results in resource leaks.

The iproc driver always returns 0, it's just a bit hidden. So make
iproc_pcie_remove() return void instead of always zero and convert the
platform driver to the alternative remove callback that returns void and
eventually replaces the int returning callback.

Link: https://lore.kernel.org/linux-pci/20230321193208.366561-9-u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>