soc: qcom: fix to avoid multiple memory allocations

There is a chance that glink channel memory can be allocated multiple
times if wdsp_glink_ch_info_init() is called from multiple threads.
Avoid this scenario by protecting the private data structure.

Change-Id: I04fc19232b0f128b36a00dc1e73a3bed03664a93
Signed-off-by: Vidyakumar Athota <vathota@codeaurora.org>