chore: remove unnecessary NULL checks

Fix #1494

Author: CarterLi

src/detection/diskio/diskio_bsd.c

@@ -99,8 +99,7 @@ const char* ffDiskIOGetIoCounters(FFlist* result, FFDiskIOOptions* options)
         device->writeCount = current->num_writes;
     }
 
-    if (stats.dinfo->mem_ptr)
-        free(stats.dinfo->mem_ptr);
+    free(stats.dinfo->mem_ptr);
     free(stats.dinfo);
 
     return NULL;

src/detection/gtk_qt/qt.c

@@ -74,8 +74,7 @@ static bool detectPlasmaFromFile(const char* filename, FFQtResult* result)
         }
     }
 
-    if(line != NULL)
-        free(line);
+    free(line);
 
     fclose(kdeglobals);