net/virtio-user: fix hugepage files enumeration

net/virtio-user: fix hugepage files enumeration

After the commit 2a04139f66b4 ("eal: add single file segments option"),
one hugepage file could contain multiple hugepages which are further
mapped to different memory regions.

Original enumeration implementation cannot handle this situation.

This patch filters out the duplicated files; and adjust the size after
the enumeration.

Fixes: 6a84c37e3975 ("net/virtio-user: add vhost-user adapter layer")

Signed-off-by: Jianfeng Tan <jianfeng.tan@intel.com>
Acked-by: Maxime Coquelin <maxime.coquelin@redhat.com>