drivers: core: Add the option SPL_DM_DEVICE_REMOVE to the Kconfig

It is currently not possible to include the support to remove devices in
the SPL. This is however needed by platforms that re-select their dtb after
DM is initialized; they need to remove all the previously bound devices
before triggering a scan of the new DT.

Add a Kconfig option to be able to include the support for device removal
in the SPL.

Signed-off-by: Jean-Jacques Hiblot <jjhiblot@ti.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

Seeries-changes:3
- update commit message
Reviewed-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Heiko Schocher <hs@denx.de>
diff --git a/drivers/core/Kconfig b/drivers/core/Kconfig
index e8ba20c..046b87a 100644
--- a/drivers/core/Kconfig
+++ b/drivers/core/Kconfig
@@ -57,13 +57,21 @@
 	default y
 	help
 	  We can save some code space by dropping support for removing a
-	  device. This is not normally required in SPL, so by default this
-	  option is disabled for SPL.
+	  device.
 
 	  Note that this may have undesirable results in the USB subsystem as
 	  it causes unplugged devices to linger around in the dm-tree, and it
 	  causes USB host controllers to not be stopped when booting the OS.
 
+config SPL_DM_DEVICE_REMOVE
+	bool "Support device removal in SPL"
+	depends on SPL_DM
+	default n
+	help
+	  We can save some code space by dropping support for removing a
+	  device. This is not normally required in SPL, so by default this
+	  option is disabled for SPL.
+
 config DM_STDIO
 	bool "Support stdio registration"
 	depends on DM