ARC: [plat-hsdk]: Enable on-board SPI NOR flash IC

HSDK board has sst26wf016b SPI NOR flash IC installed, enable it.
Acked-by: Alexey Brodkin <abrodkin@synopsys.com>
Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>

arch/arc/boot/dts/hsdk.dts

@@ -264,6 +264,14 @@ spi0: spi@20000 {
 			clocks = <&input_clk>;
 			cs-gpios = <&creg_gpio 0 GPIO_ACTIVE_LOW>,
 				   <&creg_gpio 1 GPIO_ACTIVE_LOW>;
+
+			spi-flash@0 {
+				compatible = "sst26wf016b", "jedec,spi-nor";
+				reg = <0>;
+				#address-cells = <1>;
+				#size-cells = <1>;
+				spi-max-frequency = <4000000>;
+			};
 		};
 
 		creg_gpio: gpio@14b0 {

arch/arc/configs/hsdk_defconfig

@@ -32,6 +32,8 @@ CONFIG_INET=y
 CONFIG_DEVTMPFS=y
 # CONFIG_STANDALONE is not set
 # CONFIG_PREVENT_FIRMWARE_BUILD is not set
+CONFIG_MTD=y
+CONFIG_MTD_SPI_NOR=y
 CONFIG_SCSI=y
 CONFIG_BLK_DEV_SD=y
 CONFIG_NETDEVICES=y