qcacmn: Fix 'variables may be used uninitialized' issue

Set default value for 'offset' to fix the compile issue
'variables may be used uninitialized'.

Change-Id: Ib8db38140463fb543b1d98f19743b3a3a7fded4c
CRs-Fixed: 3345183

target_if/direct_buf_rx/src/target_if_direct_buf_rx_main.c

@@ -1391,7 +1391,7 @@ static QDF_STATUS target_if_dbr_fill_ring(struct wlan_objmgr_pdev *pdev,
 	struct direct_buf_rx_buf_info *dbr_buf_pool;
 	void *buf_vaddr_unaligned, *buf_vaddr_aligned;
 	QDF_STATUS status;
-	uint8_t offset;
+	uint8_t offset = 0;
 
 	direct_buf_rx_enter();