MAINTAINERS: Fix file name for DesignWare GPIO DT schema

The commit 657a06df
  ("dt-bindings: gpio: Convert snps,dw-apb-gpio to DT schema")
missed MAINTAINERS update.

Fixes: 657a06df ("dt-bindings: gpio: Convert snps,dw-apb-gpio to DT schema")
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Serge Semin <fancer.lancer@gmail.com>
Cc: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Link: https://lore.kernel.org/r/20200520120955.68427-1-andriy.shevchenko@linux.intel.comSigned-off-by: Linus Walleij <linus.walleij@linaro.org>

MAINTAINERS

@@ -16237,7 +16237,7 @@ M:	Hoan Tran <hoan@os.amperecomputing.com>
 M:	Serge Semin <fancer.lancer@gmail.com>
 L:	linux-gpio@vger.kernel.org
 S:	Maintained
-F:	Documentation/devicetree/bindings/gpio/snps-dwapb-gpio.txt
+F:	Documentation/devicetree/bindings/gpio/snps,dw-apb-gpio.yaml
 F:	drivers/gpio/gpio-dwapb.c
 
 SYNOPSYS DESIGNWARE AXI DMAC DRIVER