MAINTAINERS: add entry for Maxim PMICs on Samsung boards

Add myself and Chanwoo Choi as supporters to help in reviewing patches
for Maxim 77686 PMIC and Maxim 14577/77693 MUIC drivers:
 - mfd (all of them),
 - extcon (extcon-max14577.c, extcon-max77693.c),
 - regulator (all of them),
 - clock (clk-max77686.c),
 - RTC (rtc-max77686.c).

Lately I am the author of contributors to them. These drivers are used
on Exynos-based boards (Trats 2, Gear 1 and Gear 2).

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Cc: MyungJoo Ham <myungjoo.ham@samsung.com>
Cc: Chanwoo Choi <cw00.choi@samsung.com>
Cc: Samuel Ortiz <sameo@linux.intel.com>
Cc: Lee Jones <lee.jones@linaro.org>
Cc: Liam Girdwood <lgirdwood@gmail.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Mike Turquette <mturquette@linaro.org>
Cc: Stephen Boyd <sboyd@codeaurora.org>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Acked-by: Mark Brown <broonie@kernel.org>
Acked-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>