dsp: Fix NOC error from lpass on accessing LPASS_AVTIMER_LSB

avcs_core_query_timer_offset can be called from external ioctl
while avtimer clk count is 0. This can result in a NOC while
reading avtimer register. Reset adsp_ready if avtimer clk count
is 0 to resolve the issue.

Change-Id: I3d088c306f4895a2fee68f2ac95ea6ad96094ea1
Signed-off-by: Vatsal Bucha <vbucha@codeaurora.org>