of: clean up OF_CONTROL ifdef conditionals

We have flipped CONFIG_SPL_DISABLE_OF_CONTROL.  We have cleansing
devices, $(SPL_) and CONFIG_IS_ENABLED(), so we are ready to clear
away the ugly logic in include/fdtdec.h:

 #ifdef CONFIG_OF_CONTROL
 # if defined(CONFIG_SPL_BUILD) && !defined(SPL_OF_CONTROL)
 #  define OF_CONTROL 0
 # else
 #  define OF_CONTROL 1
 # endif
 #else
 # define OF_CONTROL 0
 #endif

Now CONFIG_IS_ENABLED(OF_CONTROL) is the substitute.  It refers to
CONFIG_OF_CONTROL for U-boot proper and CONFIG_SPL_OF_CONTROL for
SPL.

Also, we no longer have to cancel CONFIG_OF_CONTROL in
include/config_uncmd_spl.h and scripts/Makefile.spl.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
diff --git a/drivers/sound/max98095.c b/drivers/sound/max98095.c
index febf419..35829f8 100644
--- a/drivers/sound/max98095.c
+++ b/drivers/sound/max98095.c
@@ -520,7 +520,7 @@
 				const void *blob)
 {
 	int error = 0;
-#ifdef CONFIG_OF_CONTROL
+#if CONFIG_IS_ENABLED(OF_CONTROL)
 	enum fdt_compat_id compat;
 	int node;
 	int parent;
diff --git a/drivers/sound/wm8994.c b/drivers/sound/wm8994.c
index f8e9a6e..d378442 100644
--- a/drivers/sound/wm8994.c
+++ b/drivers/sound/wm8994.c
@@ -814,7 +814,7 @@
 			const void *blob)
 {
 	int error = 0;
-#ifdef CONFIG_OF_CONTROL
+#if CONFIG_IS_ENABLED(OF_CONTROL)
 	enum fdt_compat_id compat;
 	int node;
 	int parent;