hal: fix null pointer reference

Add null pointer check to fix null pointer reference

CRs-Fixed: 2334050
Change-Id: Ib2f82eb9730c4a517f247847059b192f199734e4
diff --git a/hal/msm8974/platform.c b/hal/msm8974/platform.c
index 0766311..390a9eb 100644
--- a/hal/msm8974/platform.c
+++ b/hal/msm8974/platform.c
@@ -5084,7 +5084,15 @@
             platform->spkr_ch_map->num_ch = num_ch;
             for (i = 0; i < num_ch; i++) {
                 opts = strtok_r(NULL, ", ", &test_r);
-                platform->spkr_ch_map->chmap[i] = strtoul(opts, NULL, 16);
+                if (opts == NULL) {
+                    ALOGE("%s: incorrect ch_map\n", __func__);
+                    free(platform->spkr_ch_map);
+                    platform->spkr_ch_map = NULL;
+                    str_parms_del(parms, AUDIO_PARAMETER_KEY_SPKR_DEVICE_CHMAP);
+                    return;
+                } else {
+                    platform->spkr_ch_map->chmap[i] = strtoul(opts, NULL, 16);
+                }
             }
         }
         str_parms_del(parms, AUDIO_PARAMETER_KEY_SPKR_DEVICE_CHMAP);