ASoC: mdm9607: Fix to avoid NULL pointer dereference

Pointer to machine data structure is deferenced in error
case where it is NULL. Fix to avoid this possible
NULL pointer dereference.

CRs-Fixed: 1037404
Change-Id: I604b2ca0d59354fe3a45cdc8ea0c41e78ef41263
Signed-off-by: Viraja Kommaraju <virajak@codeaurora.org>