Documentation/process: maintainer-soc: Be more explicit about defconfig

It is already documented but people still send noticeable amount of
patches ignoring the rule - get_maintainers.pl does not work on
arm64/configs/defconfig or any other shared ARM defconfig.

Be more explicit, that one must not rely on typical/simple approach
here for getting To/Cc list.

Signed-off-by: Krzysztof Kozlowski <[e-mail]>
Reviewed-by: Linus Walleij <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Arnd Bergmann <[e-mail]>

Documentation/process/maintainer-soc.rst

···
 
 All typical platform related patches should be sent via SoC submaintainers
 (platform-specific maintainers).  This includes also changes to per-platform or
-shared defconfigs (scripts/get_maintainer.pl might not provide correct
-addresses in such case).
+shared defconfigs. Note that scripts/get_maintainer.pl might not provide
+correct addresses for the shared defconfig, so ignore its output and manually
+create CC-list based on MAINTAINERS file or use something like
+``scripts/get_maintainer.pl -f drivers/soc/FOO/``).
 
 Submitting Patches to the Main SoC Maintainers
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~