ble: crypto: Remove NORDIC_SECURITY_BACKEND for ECDH with nrf_oberon

-This commit removes selection of legacy crypto just to get acces
 to nrf_oberon (and ocrypto_ prefixed APIs)
-This commit enables NRF_OBERON regardless if TF-M is enabled or not

ref: NCSDK-29217

Signed-off-by: Frank Audun Kvamtrø <[email protected]>

Author: frkv

subsys/bluetooth/controller/Kconfig

@@ -360,8 +360,7 @@ choice BT_CTLR_ECDH_LIB
 	prompt "SoftDevice Controller ECDH library"
 
 config BT_CTLR_ECDH_LIB_OBERON
-	select NRF_OBERON if !BUILD_WITH_TFM
-	select NORDIC_SECURITY_BACKEND if BUILD_WITH_TFM
+	select NRF_OBERON
 	depends on !SOC_SERIES_BSIM_NRFXX
 	bool "nRF Oberon (SW)"