The Simple Pairing process can only be used if both sides have the
support enabled in the host stack. The current Bluetooth specification
has three ways to detect this support.

If an Extended Inquiry Result has been sent during inquiry then it
is safe to assume that Simple Pairing is enabled. It is not allowed
to enable Extended Inquiry without Simple Pairing. During the remote
name request phase a notification with the remote host supported
features will be sent to indicate Simple Pairing support. Also the
second page of the remote extended features can indicate support for
Simple Pairing.

For all three cases the value of remote Simple Pairing mode is stored
in the inquiry cache for later use.
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>