MIPS: ath79: Rename dev-ar913x-wmac.c to dev-wmac.c

Rename the file as a last step of the 'ar913x' removal changes.
Signed-off-by: Gabor Juhos <juhosg@openwrt.org>
Cc: Imre Kaloz <kaloz@openwrt.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/3034/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/ath79/Makefile

@@ -20,7 +20,7 @@ obj-$(CONFIG_ATH79_DEV_GPIO_BUTTONS)	+= dev-gpio-buttons.o
 obj-$(CONFIG_ATH79_DEV_LEDS_GPIO)	+= dev-leds-gpio.o
 obj-$(CONFIG_ATH79_DEV_SPI)		+= dev-spi.o
 obj-$(CONFIG_ATH79_DEV_USB)		+= dev-usb.o
-obj-$(CONFIG_ATH79_DEV_WMAC)		+= dev-ar913x-wmac.o
+obj-$(CONFIG_ATH79_DEV_WMAC)		+= dev-wmac.o
 
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