net/netvsc: replace compiler builtin overflow check

net/netvsc: replace compiler builtin overflow check

'__builtin_add_overflow' added to gcc in version 5, earlier versions
causing build error, like gcc 4.8.5 in RHEL7.

Replaced compiler builtin check with arithmetic check.

Fixes: 7838d3a6ae7a ("net/netvsc: check for overflow on packet info from host")

Reported-by: Raslan Darawsheh <rasland@mellanox.com>
Signed-off-by: Ferruh Yigit <ferruh.yigit@intel.com>
Acked-by: Stephen Hemminger <stephen@networkplumber.org>
Tested-by: Raslan Darawsheh <rasland@nvidia.com>
Tested-by: Ajit Khaparde <ajit.khaparde@broadcom.com>