1) Using fwctx variable after brcmf_fw_request_done() was executed meant
accessing freed memory.
2) Using fwctx->completion for the wait_for_completion_timeout() call
could reuslt in NULL pointer dereference on fw loading error or if
brcmf_fw_request_done() was executed quickly enough.
Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
