Bluetooth: hci_qca: Use vfree() instead of kfree()

Use vfree() instead of kfree() to free vmalloc()
allocated data.

Fixes: d841502c ("Bluetooth: hci_qca: Collect controller memory dump during SSR")
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Reviewed-by: Balakrishna Godavarthi <bgodavar@codeaurora.org>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>