soc: qcom: wda: Disable powersave work on deinitialization

A delayed powersave work may not be cancelled if it re-arms itself.
This could lead to invalid memory access after the work is destroyed.
This change prevents the powersave work from re-queueing during
deinitialization process.

Change-Id: Ib5257c05e10e2e12c64ec28043ad0664574ccf97
Acked-by: Weiyi Chen <weiyic@qti.qualcomm.com>
Signed-off-by: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>