floss: Don't call delete stored link key

Write and Delete Stored Link Key aren't useful anymore with modern
controllers since we no longer store link keys for boot mode. For now,
ifdef them away for Floss.

Bug: 250493092
Test: Manually verified with classic pairing
Tag: #floss
Change-Id: I89f3ff58145fd8851328f85a2499fbd4f40f4aae