hwrng: exynos - Enable COMPILE_TEST

Get some build coverage of Exynos H/W random number generator
driver. Driver uses devm_ioremap_resource() so add IOMEM dependency for
the compile testing.
Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/char/hw_random/Kconfig

@@ -309,7 +309,8 @@ config HW_RANDOM_POWERNV
 
 config HW_RANDOM_EXYNOS
 	tristate "EXYNOS HW random number generator support"
-	depends on ARCH_EXYNOS
+	depends on ARCH_EXYNOS || COMPILE_TEST
+	depends on HAS_IOMEM
 	default HW_RANDOM
 	---help---
 	  This driver provides kernel-side support for the Random Number