ijksdl: fix audiotrack init with non-stereo channel

ijkmediaplayer/jni/ijksdl/android/ijksdl_android_jni.c

@@ -61,12 +61,15 @@ jint SDL_AndroidJni_SetupThreadEnv(JNIEnv **p_env)
     pthread_once(&g_key_once, make_thread_key);
 
     JNIEnv *env = (JNIEnv*) pthread_getspecific(g_thread_key);
-    if (!env) {
-        if ((*jvm)->AttachCurrentThread(jvm, &env, NULL) == JNI_OK) {
-            pthread_setspecific(g_thread_key, env);
-            *p_env = env;
-            return 0;
-        }
+    if (env) {
+        *p_env = env;
+        return 0;
+    }
+
+    if ((*jvm)->AttachCurrentThread(jvm, &env, NULL) == JNI_OK) {
+        pthread_setspecific(g_thread_key, env);
+        *p_env = env;
+        return 0;
     }
 
     return -1;