[nrf fromtree] Bluetooth: Increase RX thread stack size

Normal usage for Bluetooth applications are getting close to or
already overflowing the default BT RX stack size of 1024.

For example:
 - Discovery using the fixed ATT channel used 984 bytes.
 - Discovery using an enhanced ATT channel used 1048 bytes,
   which would lead to stack overflow using the default BT RX thread
   stack size.

Signed-off-by: Herman Berget <[email protected]>
(cherry picked from commit 5ace0e8)

Author: hermabe

subsys/bluetooth/host/Kconfig

@@ -129,7 +129,7 @@ config BT_RX_STACK_SIZE
 	default 2200 if BT_MESH
 	default 2048 if BT_AUDIO
 	default 2200 if BT_SETTINGS
-	default 1024
+	default 1200
 	help
 	  Size of the receiving thread stack. This is the context from
 	  which all event callbacks to the application occur. The