pinctrl: pistachio: fix use of irq_of_parse_and_map()

The irq_of_parse_and_map() function returns 0 on failure, and does not
return an negative value.

Fixes: cefc03e5 ("pinctrl: Add Pistachio SoC pin control driver")
Reported-by: Zeal Robot <zealci@zte.com.cn>
Signed-off-by: Lv Ruyi <lv.ruyi@zte.com.cn>
Link: https://lore.kernel.org/r/20220424031430.3170759-1-lv.ruyi@zte.com.cn


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