MAINTAINERS: Add DTS files to patterns for Samsung platform

Help ensure that updates to the Samsung device trees get sent to the
Samsung maintainers for review by adding file patterns to MAINTAINERS.
Signed-off-by: Mark Brown <broonie@linaro.org>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>

MAINTAINERS

@@ -1154,6 +1154,8 @@ L:	linux-arm-kernel@lists.infradead.org (moderated for non-subscribers)
 L:	linux-samsung-soc@vger.kernel.org (moderated for non-subscribers)
 W:	http://www.fluff.org/ben/linux/
 S:	Maintained
+F:	arch/arm/boot/dts/s3c*
+F:	arch/arm/boot/dts/exynos*
 F:	arch/arm/plat-samsung/
 F:	arch/arm/mach-s3c24*/
 F:	arch/arm/mach-s3c64xx/