Build error has been reported by Intel build system:
SUSE12SP3_64 / Linux 3.7.10-1 / GCC 4.7.2
lib/librte_vhost/vhost_crypto.c: In function ‘rte_vhost_crypto_set_zero_copy’:
lib/librte_vhost/vhost_crypto.c:1192:2: error:
comparison of unsigned expression < 0 is always false
As enums can be either signed or unsigned, this patch removes
the negative check and cast to unsigned the upper limit check.
Fixes: 939066d965 ("vhost/crypto: add public function implementation")
Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>