boards: native_sim: enable ENTROPY_GENERATOR if BT

On the native_sim platform, BT relies on Mbed TLS to implement
PSA Crypto API. This library requires a valid entropy source
to initialize properly. Therefore we enable ENTROPY_GENERATOR
at board level instead of editing _all_ the samples/tests
configuration files to make a more compact change.

Signed-off-by: Valerio Setti <[email protected]>

Author: valeriosetti

boards/native/native_sim/Kconfig.defconfig

@@ -32,5 +32,14 @@ config UART_CONSOLE
 
 endif # CONSOLE
 
+# BT relies on PSA Crypto API to perform crypto operations. On this platform
+# this is implemented by Mbed TLS which requires a (possibly true) random
+# number generator to initialize properly. We enable ENTROPY_GENERATOR here
+# instead of manually adding it to all samples/tests configuration files because
+# it looks more compact and easier to maintain.
+config ENTROPY_GENERATOR
+	bool
+	default y if BT
+
 
 endif # BOARD_NATIVE_SIM