dsp: ensure unmap memory is called when PDR/SSR

During PDR/SSR, hyp assign is not called when stop
call in below cases:
1. cvs and mvm handle are not null
2. disable voice path failure during device switch

Fix it by ensuring unmap memory is called during
PDR/SSR.

Change-Id: I37b66a6f6dc29934dde0b0814ab44b784ebe2aea
Signed-off-by: Kunlei Zhang <kunleiz@codeaurora.org>