MAINTAINERS: Remove Javier Martinez Canillas as reviewer for Exynos

I left Samsung and lost access to most Exynos hardware and documentation.
Also, I likely won't be able to keep an eye on the platform anymore in the
short term so remove myself as a reviewer for Exynos.

Signed-off-by: Javier Martinez Canillas <javier@dowhile0.org>
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>

MAINTAINERS

@@ -1692,7 +1692,6 @@ N:	rockchip
 ARM/SAMSUNG EXYNOS ARM ARCHITECTURES
 M:	Kukjin Kim <kgene@kernel.org>
 M:	Krzysztof Kozlowski <krzk@kernel.org>
-R:	Javier Martinez Canillas <javier@osg.samsung.com>
 L:	linux-arm-kernel@lists.infradead.org (moderated for non-subscribers)
 L:	linux-samsung-soc@vger.kernel.org (moderated for non-subscribers)
 Q:	https://patchwork.kernel.org/project/linux-samsung-soc/list/