Bluetooth: tester: Tweak nRF52840 config

Disable stack measurements by default, since they pollute the log
output.
Ensure that the logging thread has enough stack.
Ensure that the UART that connects to the BTP client is
interrupt-driven.

Signed-off-by: Carles Cufi <[email protected]>

Author: carlescufi

tests/bluetooth/tester/boards/nrf52840_pca10056.conf

@@ -2,7 +2,8 @@
 CONFIG_TEST=n
 
 CONFIG_ASSERT=y
-CONFIG_INIT_STACKS=y
+# Enable the option below to measure stack usage
+#CONFIG_INIT_STACKS=y
 CONFIG_THREAD_NAME=y
 CONFIG_HW_STACK_PROTECTION=y
 
@@ -14,5 +15,8 @@ CONFIG_LOG_BACKEND_RTT_MODE_DROP=y
 CONFIG_USE_SEGGER_RTT=y
 CONFIG_SEGGER_RTT_BUFFER_SIZE_UP=4096
 CONFIG_LOG_BACKEND_SHOW_COLOR=n
+CONFIG_LOG_PROCESS_THREAD_STACK_SIZE=1024
 
 CONFIG_LOG_DEFAULT_LEVEL=4
+
+CONFIG_UART_INTERRUPT_DRIVEN=y