MAINTAINERS: Add Jernej Škrabec as a reviewer for Allwinner SoCs support

Jernej has helped a lot by reviewing patches recently, so let's make it
official.

Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Acked-by: Chen-Yu Tsai <wens@csie.org>
Acked-by: Jernej Skrabec <jernej.skrabec@siol.net>
Link: https://lore.kernel.org/r/20201009074423.10708-1-maxime@cerno.tech

MAINTAINERS

@@ -1546,6 +1546,7 @@ F:	drivers/clk/sunxi/
 ARM/Allwinner sunXi SoC support
 M:	Maxime Ripard <mripard@kernel.org>
 M:	Chen-Yu Tsai <wens@csie.org>
+R:	Jernej Skrabec <jernej.skrabec@siol.net>
 L:	linux-arm-kernel@lists.infradead.org (moderated for non-subscribers)
 S:	Maintained
 T:	git git://git.kernel.org/pub/scm/linux/kernel/git/sunxi/linux.git