MAINTAINERS: Add a number of "common" directories

A number of platforms have "common" directories that are in turn not
listed by the board MAINTAINERS file.  Add these directories in many
cases.

Signed-off-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/board/toradex/verdin-imx8mm/MAINTAINERS b/board/toradex/verdin-imx8mm/MAINTAINERS
index b0f4329..8217bbc 100644
--- a/board/toradex/verdin-imx8mm/MAINTAINERS
+++ b/board/toradex/verdin-imx8mm/MAINTAINERS
@@ -8,6 +8,7 @@
 F:	arch/arm/dts/imx8mm-verdin-wifi-dev.dts
 F:	arch/arm/dts/imx8mm-verdin-wifi-dev-u-boot.dtsi
 F:	board/toradex/verdin-imx8mm/
+F:	board/toradex/common/
 F:	configs/verdin-imx8mm_defconfig
 F:	doc/board/toradex/verdin-imx8mm.rst
 F:	include/configs/verdin-imx8mm.h