arm64: dts: meson: a1: Add SPIFC mux pins

SPI Flash Controller uses multi-function pins, so add missing mux
definition.

Signed-off-by: Igor Prusov <ivprusov@salutedevices.com>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://lore.kernel.org/r/20231005195543.380273-2-ivprusov@salutedevices.com
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>

Author: igor-prusov

arch/arm64/boot/dts/amlogic/meson-a1.dtsi

@@ -168,6 +168,18 @@
 						bias-pull-down;
 					};
 				};
+
+				spifc_pins: spifc {
+					mux {
+						groups = "spif_mo",
+							 "spif_mi",
+							 "spif_clk",
+							 "spif_cs",
+							 "spif_hold_n",
+							 "spif_wp_n";
+						function = "spif";
+					};
+				};
 			};
 
 			gpio_intc: interrupt-controller@440 {