fix to avoid null pointer dereference by checking
for the structure to be non-null, in below functions
wcd9378_mbhc_post_ssr_init of wcd9378-mbhc and
interpolate_zdet_val, usbcss_sysfs_store of wcd939x-mbhc.
Change-Id: I37979f969786c5490e1964913ad61123a4e09006
Signed-off-by: Srinivas Marka <quic_smarka@quicinc.com>
f804586860