MAINTAINERS: Update Peng Fan's email address

Use Peng Fan's new NXP email address in MAINTAINERS files.

Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com>
Acked-by: Peng Fan <peng.fan@nxp.com>
diff --git a/board/freescale/mx6slevk/MAINTAINERS b/board/freescale/mx6slevk/MAINTAINERS
index 2e25433..be2f3d5 100644
--- a/board/freescale/mx6slevk/MAINTAINERS
+++ b/board/freescale/mx6slevk/MAINTAINERS
@@ -1,6 +1,6 @@
 MX6SLEVK BOARD
 M:	Fabio Estevam <fabio.estevam@nxp.com>
-M:	Peng Fan <Peng.Fan@freescale.com>
+M:	Peng Fan <peng.fan@nxp.com>
 S:	Maintained
 F:	board/freescale/mx6slevk/
 F:	include/configs/mx6slevk.h