MAINTAINERS: add TI Keystone ARM platform

Adding maintainer for arch/arm/mach-keystone/
Signed-off-by: NSantosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: NKevin Hilman <khilman@linaro.org>

MAINTAINERS

@@ -965,6 +965,12 @@ M:	Lennert Buytenhek <kernel@wantstofly.org>
 L:	linux-arm-kernel@lists.infradead.org (moderated for non-subscribers)
 S:	Maintained
 
+ARM/TEXAS INSTRUMENT KEYSTONE ARCHITECTURE
+M:	Santosh Shilimkar <santosh.shilimkar@ti.com>
+L:	linux-arm-kernel@lists.infradead.org (moderated for non-subscribers)
+S:	Maintained
+F:	arch/arm/mach-keystone/
+
 ARM/LOGICPD PXA270 MACHINE SUPPORT
 M:	Lennert Buytenhek <kernel@wantstofly.org>
 L:	linux-arm-kernel@lists.infradead.org (moderated for non-subscribers)