MAINTAINERS: Replace Ley Foon Tan as Altera Mailbox maintainer

This patch replaces Ley Foon Tan as Altera Mailbox maintainer as she has
moved to a different role.

Signed-off-by: Joyce Ooi <joyce.ooi@intel.com>
Acked-by: Ley Foon Tan <lftan.linux@gmail.com>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>

MAINTAINERS

@@ -792,7 +792,7 @@ F:	Documentation/devicetree/bindings/i2c/i2c-altera.txt
 F:	drivers/i2c/busses/i2c-altera.c
 ALTERA MAILBOX DRIVER
-M:	Ley Foon Tan <ley.foon.tan@intel.com>
+M:	Joyce Ooi <joyce.ooi@intel.com>
 S:	Maintained
 F:	drivers/mailbox/mailbox-altera.c