extmod/btstack: Enable SYNC_EVENTS, PAIRING_BONDING by default.

Synchronous events work on stm32 and unix ports.
Signed-off-by: Damien George <damien@micropython.org>

extmod/btstack/btstack.mk

@@ -11,6 +11,8 @@ EXTMOD_SRC_C += extmod/btstack/modbluetooth_btstack.c
 INC += -I$(TOP)/$(BTSTACK_EXTMOD_DIR)
 
 CFLAGS_MOD += -DMICROPY_BLUETOOTH_BTSTACK=1
+CFLAGS_MOD += -DMICROPY_PY_BLUETOOTH_USE_SYNC_EVENTS=1
+CFLAGS_MOD += -DMICROPY_PY_BLUETOOTH_ENABLE_PAIRING_BONDING=1
 
 BTSTACK_DIR = $(TOP)/lib/btstack