MAINTAINERS: add brcmstb regex

This could probably consolidate a few file listings. And it satisfies
the spirit of the highly annoying [1] checkpatch warning for every new
file, though it sadly won't quash it.

[1] https://lkml.org/lkml/2014/12/17/24

Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>

MAINTAINERS

@@ -2184,6 +2184,7 @@ S:	Maintained
 F:	arch/arm/mach-bcm/*brcmstb*
 F:	arch/arm/boot/dts/bcm7*.dts*
 F:	drivers/bus/brcmstb_gisb.c
+N:	brcmstb
 
 BROADCOM BMIPS MIPS ARCHITECTURE
 M:	Kevin Cernekee <cernekee@gmail.com>