regulator: maintainers - add maintainers for regulator framework.

Adds Liam Girdwood and Mark Brown as regulator framework maintainers.

Signed-off-by: Liam Girdwood <[e-mail]>

MAINTAINERS

···
 L:	[e-mail]
 S:	Maintained
 
+VOLTAGE AND CURRENT REGULATOR FRAMEWORK
+P:	Liam Girdwood
+M:	[e-mail]
+P:	Mark Brown
+M:	[e-mail]
+W:	http://opensource.wolfsonmicro.com/node/15
+T:	git kernel.org/pub/scm/linux/kernel/git/lrg/voltage-2.6.git
+S:	Supported
+
 VT1211 HARDWARE MONITOR DRIVER
 P:	Juerg Haefliger
 M:	[e-mail]