MAINTAINERS: correct TQ Systems DTS patterns

Fix file patterns for TQ systems DTS after re-organizing the ARM DTS
structure to fix get_maintainers.pl self-tests like:

  ./MAINTAINERS:23329: warning: no file matches	F:	arch/arm/boot/dts/imx*mba*.dts*

Fixes: 724ba675 ("ARM: dts: Move .dts files to vendor sub-directories")
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>