mips: bmips: enable the SPI flash on the Comtrend AR-5387un

It's a Macronix (mx25l12805d) 16 MB SPI flash.

Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>
Reviewed-by: Jagan Teki <jagan@openedev.com>

arch/mips/dts/comtrend,ar-5387un.dts

@@ -51,6 +51,18 @@
 	};
 };
 
+&spi {
+	status = "okay";
+
+	spi-flash@0 {
+		compatible = "spi-flash";
+		reg = <0>;
+		#address-cells = <1>;
+		#size-cells = <1>;
+		spi-max-frequency = <33333334>;
+	};
+};
+
 &uart0 {
 	u-boot,dm-pre-reloc;
 	status = "okay";

configs/comtrend_ar5387un_ram_defconfig

@@ -26,6 +26,8 @@ CONFIG_CMD_MEMINFO=y
 # CONFIG_CMD_FLASH is not set
 # CONFIG_CMD_FPGA is not set
 # CONFIG_CMD_LOADS is not set
+CONFIG_CMD_SF=y
+CONFIG_CMD_SPI=y
 # CONFIG_CMD_NET is not set
 # CONFIG_CMD_NFS is not set
 # CONFIG_CMD_MISC is not set
@@ -34,6 +36,10 @@ CONFIG_DM_GPIO=y
 CONFIG_LED=y
 CONFIG_LED_BCM6328=y
 CONFIG_LED_BLINK=y
+CONFIG_DM_SPI_FLASH=y
+CONFIG_SPI_FLASH=y
+CONFIG_SPI_FLASH_MACRONIX=y
+CONFIG_SPI_FLASH_MTD=y
 CONFIG_POWER_DOMAIN=y
 CONFIG_BCM6328_POWER_DOMAIN=y
 CONFIG_DM_RESET=y
@@ -41,3 +47,5 @@ CONFIG_RESET_BCM6345=y
 # CONFIG_SPL_SERIAL_PRESENT is not set
 CONFIG_DM_SERIAL=y
 CONFIG_BCM6345_SERIAL=y
+CONFIG_DM_SPI=y
+CONFIG_BCM63XX_HSSPI=y