hw_random: ixp4xx: enable compile-testing

The driver is almost portable already, it just needs to
include the new header for the cpu definition.

Cc: Deepak Saxena <dsaxena@plexity.net>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/char/hw_random/Kconfig

@@ -152,7 +152,7 @@ config HW_RANDOM_VIA
 
 config HW_RANDOM_IXP4XX
 	tristate "Intel IXP4xx NPU HW Pseudo-Random Number Generator support"
-	depends on ARCH_IXP4XX
+	depends on ARCH_IXP4XX || COMPILE_TEST
 	default HW_RANDOM
 	help
 	  This driver provides kernel-side support for the Pseudo-Random

drivers/char/hw_random/ixp4xx-rng.c

@@ -21,10 +21,9 @@
 #include <linux/init.h>
 #include <linux/bitops.h>
 #include <linux/hw_random.h>
+#include <linux/soc/ixp4xx/cpu.h>
 
 #include <asm/io.h>
-#include <mach/hardware.h>
-
 
 static int ixp4xx_rng_data_read(struct hwrng *rng, u32 *buffer)
 {