ASoC: wcd9xxx: Don't change button threshold registers

If registers which effect button detection are changed
when mbhc is still in recovering state, sometimes release
interrupt is not getting triggered.So don't modify registers
which effect button detection.

CRs-Fixed: 576855
Change-Id: I307ea4a112d81fecfe23eb58733913b4453284cd
Signed-off-by: Yeleswarapu, Nagaradhesh <nagaradh@codeaurora.org>