Bluetooth: hci_qca: resolve various warnings

Replace symbolic permissions with octal values. Use usleep_range
for small msec values due to the fact that msleep() less than
20ms may have unexpected behavior/sleep longer.

- https://lkml.org/lkml/2016/8/2/1945


- Documentation/timers/timers-howto.rst

Signed-off-by: Nigel Christian <nigel.l.christian@gmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>