ARM: ux500: fix clock for GPIO blocks 6 and 7

The clock assignment in the device tree for GPIO blocks 6
and 7 was incorrect, indicating this was managed by bit 1 on
PRCC 2 while it was in fact bit 11 on PRCC 2.

Acked-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

arch/arm/boot/dts/ste-dbx5x0.dtsi

@@ -197,7 +197,7 @@
 			#gpio-cells = <2>;
 			gpio-bank = <6>;
 
-			clocks = <&prcc_pclk 2 1>;
+			clocks = <&prcc_pclk 2 11>;
 		};
 
 		gpio7: gpio@8011e080 {
@@ -212,7 +212,7 @@
 			#gpio-cells = <2>;
 			gpio-bank = <7>;
 
-			clocks = <&prcc_pclk 2 1>;
+			clocks = <&prcc_pclk 2 11>;
 		};
 
 		gpio8: gpio@a03fe000 {