MAINTAINERS: Add maintainer for TI CC3200 SoC, board and SDK

This follows the naming policy for the TI SoC, board part number,
and SoC family name:

<board> = cc3200_launchxl
<soc> = cc3200
<series> = cc32xx
<family> = ti_simplelink

This guides directory and file naming, and Kconfig variables:
 - arch/arm/soc/<family>/<series>
 - boards/arm/<board>
 - ext/hal/cc3200sdk
 - drivers/*/<driver>_<series>.c

Jira: ZEP-1109
Change-Id: I3db9553b2cd1f34f104a5d990de9e9417fcbb3df
Signed-off-by: Gil Pitney <gil.pitney@linaro.org>