MAINTAINERS: Add missing platform maintainers for dts files

Platform dts files need to be reviewed primarily by the platform
maintainers as dts files typically go in thru their trees. Add the missing
paths where there are existing maintainers listed.

Signed-off-by: Rob Herring <robh@kernel.org>
Acked-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Acked-by: Santosh <Shilimkar&lt;ssantosh@kernel.org>
Reviewed-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Acked-by: Robert Jarzmik <robert.jarzmik@free.fr>
Acked-by: Andy Gross <agross@codeaurora.org>
Acked-by: Sudeep Holla <sudeep.holla@arm.com>
Acked-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Dinh Nguyen <dinguyen@opensource.altera.com>