MAINTAINERS, git-mailrc: Update the mmc maintainer

Update the mmc maintainer from Jaehoon to me.

Cc: Jaehoon Chung <jh80.chung@samsung.com>
Signed-off-by: Peng Fan <peng.fan@nxp.com>
Acked-by: Marek Vasut <marex@denx.de>
diff --git a/MAINTAINERS b/MAINTAINERS
index 09f31cd..7552783 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -586,7 +586,7 @@
 F:	arch/mips/mach-jz47xx/
 
 MMC
-M:	Jaehoon Chung <jh80.chung@samsung.com>
+M:	Peng Fan <peng.fan@nxp.com>
 S:	Maintained
 T:	git git://git.denx.de/u-boot-mmc.git
 F:	drivers/mmc/