ARM: ixp4xx/omixp: always include linux/leds.h

The omixp board code unconditionally defines a gpio-led
device, but for some reason includes the header file
for this only if CONFIG_LEDS_CLASS is enabled, causing
a build error otherwise.

Removing the #ifdef fixes the build error with no downsides
whatsoever.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Imre Kaloz <kaloz@openwrt.org>
Cc: Krzysztof Halasa <khc@pm.waw.pl>

arch/arm/mach-ixp4xx/omixp-setup.c

@@ -17,9 +17,7 @@
 #include <linux/serial_8250.h>
 #include <linux/mtd/mtd.h>
 #include <linux/mtd/partitions.h>
-#ifdef CONFIG_LEDS_CLASS
 #include <linux/leds.h>
-#endif
 
 #include <asm/setup.h>
 #include <asm/memory.h>