MAINTAINERS: extend mvebu SoC entry with pinctrl drivers

There was no entry for the mvebu pinctrl drivers. As they are tightly
linked to the SoCs and there is a lot of common code to support the
various pinctrl of each SoCs, then add a new entry for the mvebu
maintainers.
Reviewed-by: NThomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: NGregory CLEMENT <gregory.clement@free-electrons.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

MAINTAINERS

@@ -1495,6 +1495,7 @@ F:	arch/arm/boot/dts/armada*
 F:	arch/arm/boot/dts/kirkwood*
 F:	arch/arm64/boot/dts/marvell/armada*
 F:	drivers/cpufreq/mvebu-cpufreq.c
+F:	drivers/pinctrl/mvebu/
 F:	arch/arm/configs/mvebu_*_defconfig
 
 ARM/Marvell Berlin SoC support