MAINTAINERS: Update ARM Versatile Express platform entry

This patch update ARM Versatile Express entry to cover bits needed for
Cortex-M Prototyping System (MPS2 platform). So patches for the latter
are collected by existing Vexpress and Juno maintainers (Liviu, Sudeep,
Lorenzo) and find their way upstream via Vexpess and/or Juno trees.
Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

MAINTAINERS

@@ -1773,6 +1773,7 @@ F:	*/*/vexpress*
 F:	*/*/*/vexpress*
 F:	drivers/clk/versatile/clk-vexpress-osc.c
 F:	drivers/clocksource/versatile.c
+N:	mps2
 
 ARM/VFP SUPPORT
 M:	Russell King <linux@arm.linux.org.uk>