MAINTAINERS: gemini: add missing dts pattern

The MAINTAINERS entry for cortina/gemini miss all dts of this platform.

Signed-off-by: Corentin Labbe <clabbe@baylibre.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

MAINTAINERS

@@ -1810,6 +1810,7 @@ F:	Documentation/devicetree/bindings/arm/gemini.txt
 F:	Documentation/devicetree/bindings/net/cortina,gemini-ethernet.txt
 F:	Documentation/devicetree/bindings/pinctrl/cortina,gemini-pinctrl.txt
 F:	Documentation/devicetree/bindings/rtc/faraday,ftrtc010.txt
+F:	arch/arm/boot/dts/gemini*
 F:	arch/arm/mach-gemini/
 F:	drivers/net/ethernet/cortina/
 F:	drivers/pinctrl/pinctrl-gemini.c