modules: mbedtls: add name for implementation choice symbol

Add a name for the Kconfig choice symbol
indicating the mbedtls implementation.

Signed-off-by: Ioannis Glaropoulos <[email protected]>

Author: ioannisg

modules/mbedtls/Kconfig

@@ -13,7 +13,7 @@ menuconfig MBEDTLS
 
 if MBEDTLS
 
-choice
+choice MBEDTLS_IMPLEMENTATION
 	prompt "Select implementation"
 	default MBEDTLS_BUILTIN