ASoC: msm: qdsp6v2: clear old memhandle list when SSR happens

When SSR triggers, ASM gets RESET_EVENT callback.
Clear custom topology related old memhandle list here.
Otherwise for next ASM session opened after SSR,
old memhandle is sent to DSP and result in no audio.
Also, for ASM session while unmap during SSR, APR
command fail is expected, even then go ahead and
clear old mem handles relating to session.
Add changes to clear it from list.

CRs-Fixed: 592823, 589762, 592580, 590719, 589450, 593497
Change-Id: I10fc8190e929c7a4a344b1d393233e6cbcfcee97
Signed-off-by: Laxminath Kasam <lkasam@codeaurora.org>