pinctrl: sunxi: h6-r: Add s_rsb pin functions

As there is an RSB controller in the H6 SoC, there should be some pin
configuration for it. While no such configuration is documented, the
"s_i2c" pins are suspiciously on the "alternate" function 3, with no
primary function 2 given. This suggests the primary function for these
pins is actually RSB, and that is indeed the case.

Add the "s_rsb" pin functions so the RSB controller can be used.

Signed-off-by: Samuel Holland <[e-mail]>
Acked-by: Chen-Yu Tsai <[e-mail]>
Acked-by: Maxime Ripard <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Linus Walleij <[e-mail]>

drivers/pinctrl/sunxi/pinctrl-sun50i-h6-r.c

···
 	SUNXI_PIN(SUNXI_PINCTRL_PIN(L, 0),
 		  SUNXI_FUNCTION(0x0, "gpio_in"),
 		  SUNXI_FUNCTION(0x1, "gpio_out"),
+		  SUNXI_FUNCTION(0x2, "s_rsb"),		/* SCK */
 		  SUNXI_FUNCTION(0x3, "s_i2c"),		/* SCK */
 		  SUNXI_FUNCTION_IRQ_BANK(0x6, 0, 0)),	/* PL_EINT0 */
 	SUNXI_PIN(SUNXI_PINCTRL_PIN(L, 1),
 		  SUNXI_FUNCTION(0x0, "gpio_in"),
 		  SUNXI_FUNCTION(0x1, "gpio_out"),
+		  SUNXI_FUNCTION(0x2, "s_rsb"),		/* SDA */
 		  SUNXI_FUNCTION(0x3, "s_i2c"),		/* SDA */
 		  SUNXI_FUNCTION_IRQ_BANK(0x6, 0, 1)),	/* PL_EINT1 */
 	SUNXI_PIN(SUNXI_PINCTRL_PIN(L, 2),