kernel.bbclass: Optionally create lib dir during deploy

kernel.bbclass: Optionally create lib dir during deploy

when we have multilib and a 64bit machine and initramfs then image/lib
directory will not be created and it will end up with errors like

| DEBUG: Executing python function sstate_task_prefunc
| DEBUG: Python function sstate_task_prefunc finished
| DEBUG: Executing shell function do_deploy
| tar: lib: Cannot stat: No such file or directory
| tar: Exiting with failure status due to previous errors

So in order to overcome this shortcoming lets mkdir -p the
lib directory so the modules can be happily installed.

(From OE-Core rev: 3f501204f375cc40a14597a25cb09faaba9ff802)

Signed-off-by: Khem Raj <raj.khem@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>