MAINTAINERS: update brcm dts pattern

Commit 8c0b9ee8 ("MIPS: Move device-trees into vendor
sub-directories") moved the files, update the pattern.
Signed-off-by: NJoe Perches <joe@perches.com>
Cc: Andrew Bresticker <abrestic@chromium.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

MAINTAINERS

@@ -2280,7 +2280,7 @@ S:	Maintained
 F:	arch/mips/bmips/*
 F:	arch/mips/include/asm/mach-bmips/*
 F:	arch/mips/kernel/*bmips*
-F:	arch/mips/boot/dts/bcm*.dts*
+F:	arch/mips/boot/dts/brcm/bcm*.dts*
 F:	drivers/irqchip/irq-bcm7*
 F:	drivers/irqchip/irq-brcmstb*