MAINTAINERS: git-mailrc: update maintainer for Rockchip

Send patch to Kever Yang instead of Lin Huang for Rockchip patches,
for Lin is not always working on upstream U-Boot.

Signed-off-by: Kever Yang <kever.yang@rock-chips.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Changed , to : in subject:
Signed-off-by: Simon Glass <sjg@chromium.org>

doc/git-mailrc

@@ -77,7 +77,7 @@ alias tegra2         tegra
 alias ti             uboot, trini
 alias uniphier       uboot, masahiro
 alias zynq           uboot, monstr
-alias rockchip       uboot, sjg, Lin huang <hl@rock-chips.com>
+alias rockchip       uboot, sjg, Kever Yang <kever.yang@rock-chips.com>
 alias avr32          uboot, abiessmann
 
 alias bfin           uboot, vapier, sonic