dts: renamed FIT_EMBED to MULTI_DTB_FIT and moved it to the dts Kconfig

CONFIG_FIT_EMBED might be confused with CONFIG_OF_EMBED, rename it
MULTI_DTB_FIT as it is able to get a DTB from a FIT image containing
multiple DTBs. Also move the option to the Kconfig dedicated to the DTS
options and create a README for this feature.

Signed-off-by: Jean-Jacques Hiblot <jjhiblot@ti.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/common/Kconfig b/common/Kconfig
index 3c99650..f96a25f 100644
--- a/common/Kconfig
+++ b/common/Kconfig
@@ -403,22 +403,6 @@
 
 endmenu
 
-config DTB_RESELECT
-	bool "Support swapping dtbs at a later point in boot"
-	depends on FIT_EMBED
-	help
-	  It is possible during initial boot you may need to use a generic
-	  dtb until you can fully determine the board your running on. This
-	  config allows boards to implement a function at a later point
-	  during boot to switch to the "correct" dtb.
-
-config FIT_EMBED
-	bool "Support a FIT image embedded in the U-boot image"
-	help
-	  This option provides hooks to allow U-boot to parse an
-	  appended FIT image and enable board specific code to then select
-	  the correct DTB to be used.
-
 config DEFAULT_FDT_FILE
 	string "Default fdt file"
 	help
diff --git a/common/Makefile b/common/Makefile
index 801ea31..cec506f 100644
--- a/common/Makefile
+++ b/common/Makefile
@@ -103,7 +103,7 @@
 obj-$(CONFIG_ANDROID_BOOT_IMAGE) += image-android.o
 obj-$(CONFIG_$(SPL_TPL_)OF_LIBFDT) += image-fdt.o
 obj-$(CONFIG_$(SPL_TPL_)FIT) += image-fit.o
-obj-$(CONFIG_FIT_EMBED) += boot_fit.o common_fit.o
+obj-$(CONFIG_$(SPL_)MULTI_DTB_FIT) += boot_fit.o common_fit.o
 obj-$(CONFIG_$(SPL_TPL_)FIT_SIGNATURE) += image-sig.o
 obj-$(CONFIG_IO_TRACE) += iotrace.o
 obj-y += memsize.o