Bluetooth: qca: fix info leak when fetching board id

commit 0adcf6be upstream.

Add the missing sanity check when fetching the board id to avoid leaking
slab data when later requesting the firmware.

Fixes: a7f8dedb ("Bluetooth: qca: add support for QCA2066")
Cc: stable@vger.kernel.org	# 6.7
Cc: Tim Jiang <quic_tjiang@quicinc.com>
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>