mmc: usdhi6rol0: Add maintainers

The usdhi6rol0 driver is exclusively used for the ARTPEC family of
SoCs. Other SoCs with the same IP of Panasonic origin use the tmio_mmc
driver. Therefore we assigner maintainer responsibility to us at Axis
until the two drivers become unified.
Signed-off-by: NLars Persson <larper@axis.com>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

MAINTAINERS

@@ -1471,6 +1471,7 @@ F:	arch/arm/mach-artpec
 F:	arch/arm/boot/dts/artpec6*
 F:	drivers/clk/axis
 F:	drivers/crypto/axis
+F:	drivers/mmc/host/usdhi6rol0.c
 F:	drivers/pinctrl/pinctrl-artpec*
 F:	Documentation/devicetree/bindings/pinctrl/axis,artpec6-pinctrl.txt