unittest_gpio_remove() is only called after unittest_gpio_probe() completed
successfully. In this case driver data was set to a non-NULL value and so
platform_get_drvdata() never returns NULL.

Also note that the compiler might optimize away this check anyhow as
devptr was already dereferenced for the dev_dbg call above.

Drop this if block.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20230319100620.295849-3-u.kleine-koenig@pengutronix.deSigned-off-by: Rob Herring <robh@kernel.org>