Store the link key derived from cross tranport link key

Use case: PTS test case for cross transport link key
derivation

Steps to reproduce:
1. Start Test case GAP TP/LEP/DM/BV-15 in PTSv6.0

Failure: PTS test case TP/LEP/DM/BV-15 fails as the link
key is not stored when the key is derived from other
transport key. So it will again go for pairing even though
it has link key but not stored.

Root cause: Link key is stored only when bond type is
presistent, but it sets the bond type to persistent only
when it receives SSP request but not link key is derived.

Fix: So making the solution generic to store always when the
link key type is authenticated combination key with P-256.

Bug: 22486860
Change-Id: I3eb201262f72c86a9438351cad14a6698065fa90