hw/cxl: Fix uint32 overflow cxl-mailbox-utils.c

The sum offset + length may overflow uint32. Since this sum is
compared with uint64_t return value of get_lsa_size(), it makes
sense to choose uint64_t type for offset and length.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: 3ebe676a3463 ("hw/cxl/device: Implement get/set Label Storage Area (LSA)")
Signed-off-by: Dmitry Frolov <frolov@swemel.ru>
Link: https://lore.kernel.org/r/20240917080925.270597-2-frolov@swemel.ru
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Message-Id: <20241014121902.2146424-2-Jonathan.Cameron@huawei.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

hw/cxl/cxl-mailbox-utils.c

@@ -1445,7 +1445,7 @@ static CXLRetCode cmd_ccls_get_lsa(const struct cxl_cmd *cmd,
     } QEMU_PACKED *get_lsa;
     CXLType3Dev *ct3d = CXL_TYPE3(cci->d);
     CXLType3Class *cvc = CXL_TYPE3_GET_CLASS(ct3d);
-    uint32_t offset, length;
+    uint64_t offset, length;
 
     get_lsa = (void *)payload_in;
     offset = get_lsa->offset;