ARM: dts: imx7d: Correct speed grading fuse settings

The 800MHz opp speed grading fuse mask should be 0xd instead
of 0xf according to fuse map definition:

SPEED_GRADING[1:0]	MHz
	00		800
	01		500
	10		1000
	11		1200
Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Reviewed-by: Leonard Crestez <leonard.crestez@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm/boot/dts/imx7d.dtsi

@@ -43,7 +43,7 @@ opp-792000000 {
 			opp-hz = /bits/ 64 <792000000>;
 			opp-microvolt = <1000000>;
 			clock-latency-ns = <150000>;
-			opp-supported-hw = <0xf>, <0xf>;
+			opp-supported-hw = <0xd>, <0xf>;
 		};
 
 		opp-996000000 {