ARM: uniphier: switch to CONFIG_ENV_IS_NOWHERE

The non-volatile storage varies board by board.  The default should
be NOWHERE.  Please choose a proper device via Kconfig.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
diff --git a/env/Kconfig b/env/Kconfig
index 024d4d7..20516a5 100644
--- a/env/Kconfig
+++ b/env/Kconfig
@@ -3,7 +3,6 @@
 choice
 	prompt "Select the location of the environment"
 	default ENV_IS_IN_MMC if ARCH_SUNXI
-	default ENV_IS_IN_MMC if ARCH_UNIPHIER
 	default ENV_IS_IN_MMC if ARCH_EXYNOS4
 	default ENV_IS_IN_MMC if MX6SX || MX7D
 	default ENV_IS_IN_MMC if TEGRA30 || TEGRA124