ASoC: wcd-mbhc: Fix special headset detection issue

Even if the first measurement of hs_comp_result is 0 after
micbias is increased to 2.7v, it should be reported as special
headset. Fix the condition in driver to handle this scenario.

CRs-Fixed: 993103
Change-Id: I859e9de29436af12ef1af0e2ed85bcbb51d2e27a
Signed-off-by: Yeleswarapu Nagaradhesh <nagaradh@codeaurora.org>