MAINTAINERS: update brcm gpio filename pattern

Commit 23a71fd6 ("dt-bindings: brcm: rationalize Broadcom
documentation naming") renamed the file, update the pattern.

Signed-off-by: Joe Perches <joe@perches.com>
Acked-by: Scott Branden <sbranden@broadcom.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

MAINTAINERS

@@ -2339,7 +2339,7 @@ M:	Ray Jui <rjui@broadcom.com>
 L:	bcm-kernel-feedback-list@broadcom.com
 S:	Supported
 F:	drivers/gpio/gpio-bcm-kona.c
-F:	Documentation/devicetree/bindings/gpio/gpio-bcm-kona.txt
+F:	Documentation/devicetree/bindings/gpio/brcm,kona-gpio.txt
 
 BROADCOM NVRAM DRIVER
 M:	Rafał Miłecki <zajec5@gmail.com>