Shell command to clear the PMKSA cache

Added wifi shell command to clear the PMK cache
associated with the network id.

Bug: 168860490
Test: Manual - cleared the pmksa cache and tested re-connection
and confirmed from logs that PMKID/open mode auth is not used.

Change-Id: Ief30058da2c963cca0460d04063c306c87d8d8de
1 file changed