ARM: dts: armada388-clearfog: increase speed of i2c0 to 400kHz

All the devices on I2C0 support fast mode, so increase the bus speed
to match.  The Armada 388 is known to have a timing issue when in
standard mode, which we believe causes the ficticious device at 0x64
to appear.

[gregory.clement@bootlin.com: Note that since the commit fbffee74
("ARM: dts: Fix I2C repeated start issue on Armada-38x") in 4.14, the
timing issue is managed for the Armada 38x SoCs.]
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>

arch/arm/boot/dts/armada-388-clearfog.dtsi

@@ -143,8 +143,7 @@ fixed-link {
 };
 
 &i2c0 {
-	/* Is there anything on this? */
-	clock-frequency = <100000>;
+	clock-frequency = <400000>;
 	pinctrl-0 = <&i2c0_pins>;
 	pinctrl-names = "default";
 	status = "okay";
@@ -239,13 +238,11 @@ sfp_mod_def0 {
 		};
 	};
 
-	/* The MCP3021 is 100kHz clock only */
+	/* The MCP3021 supports standard and fast modes */
 	mikrobus_adc: mcp3021@4c {
 		compatible = "microchip,mcp3021";
 		reg = <0x4c>;
 	};
-
-	/* Also something at 0x64 */
 };
 
 &i2c1 {