drivers: core: Add the option SPL_DM_DEVICE_REMOVE to the Kconfig

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>