Convert CONFIG_CMD_HASH to Kconfig

This converts the following to Kconfig:
   CONFIG_CMD_HASH

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Tom Rini <trini@konsulko.com>
[trini: Rework slightly, enable on some boards again]
Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 86b6e29..2a3a36e 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -503,6 +503,7 @@
 config TARGET_BCMCYGNUS
 	bool "Support bcmcygnus"
 	select CPU_V7
+	imply CMD_HASH
 
 config TARGET_BCMNSP
 	bool "Support bcmnsp"
diff --git a/arch/arm/include/asm/fsl_secure_boot.h b/arch/arm/include/asm/fsl_secure_boot.h
index 2e3f520..b0b3b93 100644
--- a/arch/arm/include/asm/fsl_secure_boot.h
+++ b/arch/arm/include/asm/fsl_secure_boot.h
@@ -26,7 +26,6 @@
 #define CONFIG_KEY_REVOCATION
 
 #ifndef CONFIG_SPL_BUILD
-#define CONFIG_CMD_HASH
 #ifndef CONFIG_SYS_RAMBOOT
 /* The key used for verification of next level images
  * is picked up from an Extension Table which has
diff --git a/arch/arm/mach-exynos/Kconfig b/arch/arm/mach-exynos/Kconfig
index 24cb99e..5b6c5ea 100644
--- a/arch/arm/mach-exynos/Kconfig
+++ b/arch/arm/mach-exynos/Kconfig
@@ -18,6 +18,7 @@
 	select CPU_V7
 	select BOARD_EARLY_INIT_F
 	select SHA_HW_ACCEL
+	imply CMD_HASH
 	help
 	  Samsung Exynos5 SoC family are based on ARM Cortex-A15 CPU (and
 	  Cortex-A7 CPU in big.LITTLE configuration). There are multiple SoCs