Bluetooth: Align socket option definitions with upstream kernel

The upstream kernel has acquired new BT socket options since
BT_AMP_POLICY was first defined, now BT_FLUSHABLE is option 8 and
BT_POWER is option 9.  It will save us some future pain if we align
with upstream code now and make BT_AMP_POLICY be option 10.

In addition, the option values for BT_AMP_POLICY were changed during
the upstreaming process.

CRs-fixed: 313757
Change-Id: Ia31e9c8cfd5207a6dd44e40a605d3021f5ce9fd9
Signed-off-by: Mat Martineau <mathewm@codeaurora.org>