pinctrl: nuvoton: wpcm450: off by one in wpcm450_gpio_register()

The > WPCM450_NUM_BANKS should be >= or it leads to an out of bounds
access on the next line.

Fixes: a1d1e0e3 ("pinctrl: nuvoton: Add driver for WPCM450")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
Link: https://lore.kernel.org/r/20220318071131.GA29472@kili


Signed-off-by: Linus Walleij <linus.walleij@linaro.org>