MIPS: ath79: add common USB Host Controller device

Add common platform_device and helper code to make the registration of
the built-in USB controllers easier on the board which are using them.
Also register the USB controller on the AP81 and PB44 boards.

Signed-off-by: Gabor Juhos <juhosg@openwrt.org>
Signed-off-by: Imre Kaloz <kaloz@openwrt.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/2442/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/ath79/mach-pb44.c

@@ -18,6 +18,7 @@
 #include "dev-gpio-buttons.h"
 #include "dev-leds-gpio.h"
 #include "dev-spi.h"
+#include "dev-usb.h"
 
 #define PB44_GPIO_I2C_SCL	0
 #define PB44_GPIO_I2C_SDA	1
@@ -112,6 +113,7 @@ static void __init pb44_init(void)
 					pb44_gpio_keys);
 	ath79_register_spi(&pb44_spi_data, pb44_spi_info,
 			   ARRAY_SIZE(pb44_spi_info));
+	ath79_register_usb();
 }
 
 MIPS_MACHINE(ATH79_MACH_PB44, "PB44", "Atheros PB44 reference board",