Clean up a couple variable names and declarations

Alc/ALc.c

@@ -782,13 +782,13 @@ static ATOMIC(ALCdevice*) DeviceList = ATOMIC_INIT_STATIC(NULL);
 static almtx_t ListLock;
 static inline void LockLists(void)
 {
-    int lockret = almtx_lock(&ListLock);
-    assert(lockret == althrd_success);
+    int ret = almtx_lock(&ListLock);
+    assert(ret == althrd_success);
 }
 static inline void UnlockLists(void)
 {
-    int unlockret = almtx_unlock(&ListLock);
-    assert(unlockret == althrd_success);
+    int ret = almtx_unlock(&ListLock);
+    assert(ret == althrd_success);
 }
 
 /************************************************

Alc/backends/base.c

@@ -13,10 +13,9 @@ extern inline ALuint64 GetDeviceClockTime(ALCdevice *device);
 /* Base ALCbackend method implementations. */
 void ALCbackend_Construct(ALCbackend *self, ALCdevice *device)
 {
-    int ret;
-    self->mDevice = device;
-    ret = almtx_init(&self->mMutex, almtx_recursive);
+    int ret = almtx_init(&self->mMutex, almtx_recursive);
     assert(ret == althrd_success);
+    self->mDevice = device;
 }
 
 void ALCbackend_Destruct(ALCbackend *self)