beagleconnect_freedom: Add SPI support

- Only supports master mode

Signed-off-by: Ayush Singh <[email protected]>

Author: Ayush1325

variants/beagleconnect_freedom/beagleconnect_freedom.overlay

@@ -47,5 +47,6 @@
 		builtin-led-gpios = <&gpio0 18 GPIO_ACTIVE_HIGH>;	/*  2.4GHz TX/RX  */
 		serials = <&uart0 &uart1>;
 		i2cs = <&i2c0>;
+		spis = <&spi0>;
 	};
  };