MAINTAINERS: add more name matches for Samsung SoC entries

The Samsung SoC maintainer entry covers drivers and headers matching
"exynos" name but except that there are also files for S3C24xx, S3C64xx
and S5Pv210 SoCs.  These sometimes do not have a separate entry for a
driver maintainer thus might miss review.  Add them to the Samsung SoC
maintainer entry to cover all SoCs with name matches.
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>

MAINTAINERS

@@ -2424,6 +2424,9 @@ F:	drivers/soc/samsung/
 F:	drivers/tty/serial/samsung*
 F:	include/linux/soc/samsung/
 N:	exynos
+N:	s3c2410
+N:	s3c64xx
+N:	s5pv210
 
 ARM/SAMSUNG MOBILE MACHINE SUPPORT
 M:	Kyungmin Park <kyungmin.park@samsung.com>