The function coh901318_alloc_chan_resources() calls spin_lock_irqsave()
before calling coh901318_config().
But coh901318_config() calls spin_lock_irqsave() again in its
definition, which may cause a double-lock bug.
Because coh901318_config() is only called by
coh901318_alloc_chan_resources(), the bug fix is to remove the
calls to spin-lock and -unlock functions in coh901318_config().