dsp: lsm: check for mem_map_handle

Sometimes adsp may fail to allocate memory for SVA calibration
data and add check if mem_map_handle is assigned with valid
non-zero handle to avoid panic.

Change-Id: Icad722edc52906e63d581aafa02b42b8518ebca6
Signed-off-by: Meng Wang <mengw@codeaurora.org>