usb: gadget: at91_udc: mention proper dependency

While building allmodconfig on avr32 the build failed with the error:
"at91_pmc_base" [drivers/usb/gadget/udc/atmel_usba_udc.ko] undefined!

On checking the code it turned out that if CONFIG_OF is defined then it
is using at91_pmc_read() which is using at91_pmc_base. And unless
COMMON_CLK_AT91 is defined we donot have at91_pmc_base. And
COMMON_CLK_AT91 is available with AT91 architecture.
Mention the dependency such that this driver builds with avr32 only if
OF is not enabled.
Signed-off-by: Sudip Mukherjee <sudip@vectorindia.org>
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/gadget/udc/Kconfig

@@ -55,7 +55,7 @@ config USB_LPC32XX
 
 config USB_ATMEL_USBA
 	tristate "Atmel USBA"
-	depends on AVR32 || ARCH_AT91
+	depends on ((AVR32 && !OF) || ARCH_AT91)
 	help
 	  USBA is the integrated high-speed USB Device controller on
 	  the AT32AP700x, some AT91SAM9 and AT91CAP9 processors from Atmel.