keys: update the documentation with info about "logon" keys
keys: update the documentation with info about "logon" keys

Acked-by: David Howells <ebac1d06c1688626821bb0e574a037a7a5354e49@redhat.com>
Signed-off-by: Jeff Layton <4376fbf8623cd7b7c0232225289bb91cedc0a27f@redhat.com>

KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas