vhost: fix sign extension in async split ring
vhost: fix sign extension in async split ring

Change the variable type in store_dma_desc_info_split() to fix
suspicious implicit sign extension.

Coverity issue: 370604, 370607, 370609
Fixes: 3d6cb86b0de5 ("vhost: refactor async split ring functions")

Signed-off-by: Cheng Jiang <7a6a77dd7576bfdf5dac8a9250f1050e5c53c3d0@intel.com>

john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk