Bluetooth: Make it safe to allocate buffers from TX callback
Bluetooth: Make it safe to allocate buffers from TX callback

This makes it safe to allocate buffer from the TX callback by freeing
the context before calling the callback which should wake up the TX
thread had it be pending on add_pending_tx.

Signed-off-by: Luiz Augusto von Dentz <8530c5ea66a1bdbc08f98bfcf183c8be901b5990@intel.com>

galak/zephyr,galak/zephyr,GiulianoFranchetto/zephyr,galak/zephyr,zephyrproject-rtos/zephyr,nashif/zephyr,zephyrproject-rtos/zephyr,nashif/zephyr,GiulianoFranchetto/zephyr,GiulianoFranchetto/zephyr,Vudentz/zephyr,finikorg/zephyr,nashif/zephyr,Vudentz/zephyr,Vudentz/zephyr,galak/zephyr,GiulianoFranchetto/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr,GiulianoFranchetto/zephyr,Vudentz/zephyr,finikorg/zephyr,Vudentz/zephyr,Vudentz/zephyr,finikorg/zephyr,nashif/zephyr,nashif/zephyr,zephyrproject-rtos/zephyr,galak/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr