select_cpu_clock() on cAVS currently takes all the clock locks while
adjusting them. And that function is called from clock_set_freq()
which also takes one of those locks, which leads to a recursive
spin-lock. To fix that remove per-clock spin-locks and use a global
clock lock instead.
Signed-off-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>