leds: leds-netxbig: depends on ARCH_KIRKWOOD

With the DT conversion, the board Kconfig symbols MACH_ are going to be
removed. In order to prepare this removal, this patch replaces alls the
machines dependencies for leds-netxbig by ARCH_KIRKWOOD.
Signed-off-by: Simon Guinot <simon.guinot@sequanux.org>
Acked-by: Jason Cooper <jason@lakedaemon.net>
Signed-off-by: Bryan Wu <cooloney@gmail.com>

drivers/leds/Kconfig

@@ -419,8 +419,8 @@ config LEDS_NS2
 
 config LEDS_NETXBIG
 	tristate "LED support for Big Network series LEDs"
-	depends on MACH_NET2BIG_V2 || MACH_NET5BIG_V2
 	depends on LEDS_CLASS
+	depends on ARCH_KIRKWOOD
 	default y
 	help
 	  This option enable support for LEDs found on the LaCie 2Big