ARM: uniphier: remove BLK select

This is a user configurable option, but "select BLK" forces users to
enable it.

Even with this commit, BLK is still enabled by "default y if DM_MMC"
for UniPhier SoCs; the difference is users can disable it if they
do not need it.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 7203d63..714dd8b 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -829,7 +829,6 @@
 
 config ARCH_UNIPHIER
 	bool "Socionext UniPhier SoCs"
-	select BLK
 	select CLK_UNIPHIER
 	select DM
 	select DM_GPIO