pinctrl: sunxi-pinctrl: fix pin funtion can not be match correctly.

pinctrl: sunxi-pinctrl: fix pin funtion can not be match correctly.

Pin function can not be match correctly when SUNXI_PIN describe with
mutiple variant and same function.

such as:
on pinctrl-sun4i-a10.c

SUNXI_PIN(SUNXI_PINCTRL_PIN(B, 2),
		SUNXI_FUNCTION(0x0, "gpio_in"),
		SUNXI_FUNCTION(0x1, "gpio_out"),
		SUNXI_FUNCTION_VARIANT(0x2, "pwm",    /* PWM0 */
			PINCTRL_SUN4I_A10 |
			PINCTRL_SUN7I_A20),
		SUNXI_FUNCTION_VARIANT(0x3, "pwm",    /* PWM0 */
			PINCTRL_SUN8I_R40)),

it would always match to the first variant function
(PINCTRL_SUN4I_A10, PINCTRL_SUN7I_A20)

so we should add variant compare on it.

Signed-off-by: hao_zhang <hao5781286@gmail.com>
Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>