Bluetooth: kconfig: Fix SMP dependency on BT_ECC

The Bluetooth SMP protocol depends on the BT_ECC for the LE Secure
Connections pairing. Since this feature cannot be disabled we must
select this dependency.

Signed-off-by: Joakim Andersson <joakim.andersson@nordicsemi.no>

subsys/bluetooth/host/Kconfig

diff --git a/subsys/bluetooth/host/Kconfig b/subsys/bluetooth/host/Kconfig
index 9f7a6d6..cc072b2 100644
--- a/subsys/bluetooth/host/Kconfig
+++ b/subsys/bluetooth/host/Kconfig
@@ -328,6 +328,7 @@
 	select TINYCRYPT_AES
 	select TINYCRYPT_AES_CMAC
 	select BT_RPA
+	select BT_ECC
 	help
 	  This option enables support for the Security Manager Protocol
 	  (SMP), making it possible to pair devices over LE.