MAINTAINERS: Add maintainer entry for linear ranges helper

The linear ranges helpers were refactored out of regulator core
for other drivers to enjoy. Add regulator maintainer Mark Brown as
maintainer and myself as a reviewer.

Signed-off-by: Matti Vaittinen <[email protected]>
Link: https://lore.kernel.org/r/fbbbee249c6b9df3ba63bb51ea53526b22921e84.1589866138.git.matti.vaittinen@fi.rohmeurope.com
Signed-off-by: Mark Brown <[email protected]>

Author: M-Vaittinen

MAINTAINERS

@@ -9720,6 +9720,13 @@ F:	drivers/lightnvm/
 F:	include/linux/lightnvm.h
 F:	include/uapi/linux/lightnvm.h
 
+LINEAR RANGES HELPERS
+M:	Mark Brown <[email protected]>
+R:	Matti Vaittinen <[email protected]>
+F:	lib/linear_ranges.c
+F:	lib/test_linear_ranges.c
+F:	include/linux/linear_range.h
+
 LINUX FOR POWER MACINTOSH
 M:	Benjamin Herrenschmidt <[email protected]>
 L:	[email protected]