scripts: Move Kconfig contents to cmd/Kconfig

On case-insensitive file systems we have collision between
scripts/kconfig/ directory and scripts/Kconfig file. This patch moves
scripts/Kcofnig contents to cmd/Kconfig to fix that.

Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org>
Acked-by: Masahiro Yamada <yamada.masahiro@socionext.com>

Kconfig

@@ -398,5 +398,3 @@ source "fs/Kconfig"
 source "lib/Kconfig"
 
 source "test/Kconfig"
-
-source "scripts/Kconfig"

cmd/Kconfig

@@ -116,6 +116,9 @@ endmenu
 
 source "cmd/fastboot/Kconfig"
 
+config BUILD_BIN2C
+	bool
+
 comment "Commands"
 
 menu "Info commands"

scripts/Kconfig

@@ -1,2 +0,0 @@
-config BUILD_BIN2C
-	bool