Update MAINTAINERS file for recently added reset controller, AEMIF
and clocksource driver for Keystone SOCs.

The EMIF memory controller driver is also added along with AEMIF.

Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Olof Johansson <olof@lixom.net>
Cc: Kevin Hilman <khilman@linaro.org>
Cc: Mike Turquette <mturquette@linaro.org>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NSantosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: NOlof Johansson <olof@lixom.net>