Move the log routines to the petitboot library. The log
routines are generic enough to be used for both server and
client. Does not change the log source.
jk: move to lib/log/ instead of lib/
Signed-off-by: Geoff Levand <geoffrey.levand@am.sony.com> Signed-off-by: Jeremy Kerr <jk@ozlabs.org>