MAINTAINERS: drivers/power: add entry for SmartReflex AVS drivers

The SmartReflex AVS driver evolved out of the OMAP kernel and now lives
under drivers/power/avs.

I've historically been maintainer of this but Nishanth Menon is doing most
of the heavy lifting now. Add us both as co-maintainers.

Cc: David Woodhouse <[e-mail]>
Cc: Rafael J. Wysocki <[e-mail]>
Cc: Nishanth Menon <[e-mail]>
Signed-off-by: Kevin Hilman <[e-mail]>
Signed-off-by: Anton Vorontsov <[e-mail]>

MAINTAINERS

···
 F:	Documentation/security/Smack.txt
 F:	security/smack/
 
+SMARTREFLEX DRIVERS FOR ADAPTIVE VOLTAGE SCALING (AVS)
+M:	Kevin Hilman <[e-mail]>
+M:	Nishanth Menon <[e-mail]>
+S:	Maintained
+F:	drivers/power/avs/smartreflex.c
+F:	include/linux/power/smartreflex.h
+L:	[e-mail]
+
 SMC91x ETHERNET DRIVER
 M:	Nicolas Pitre <[e-mail]>
 S:	Odd Fixes