pinctrl: at91-pio4: drop useless check in atmel_conf_pin_config_dbg_show()

pinctrl: at91-pio4: drop useless check in atmel_conf_pin_config_dbg_show()

In atmel_conf_pin_config_dbg_show(), checking atmel_pioctrl->pins[pin_id]
against being NULL doesn't make any sense as it gets derefenced first and
the driver's probe() method immediately returns -ENOMEM when devm_kzalloc()
returns NULL for any atmel_pioctrl->pins[] element anyway, thus failing to
register the device...

Found by Linux Verification Center (linuxtesting.org) with the Svace static
analysis tool.

Signed-off-by: Sergey Shtylyov <s.shtylyov@omp.ru>
Link: https://lore.kernel.org/r/4ab2f59f-45c1-76a2-94da-3331e8ec4e35@omp.ru
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>