base: Idle wait fix

Avoid unexpected idle wait

The current scheduler has possibility to missing 'ready' workload and
to deadlock, since the static variable 'queue_header' is overwritten
in the 'update_header_bits_counter' function. This patch fixes the
problem by retrying the search in case that no 'ready' workload is
found in a 'ready' workload block.

Signed-off-by: Kazunori Asayama <asayama@sm.sony.co.jp>
Signed-off-by: Yuji Mano <yuji.mano@am.sony.com>