libmlx5: Extend mlx5dv_get_qp() to return UAR mapping info

[vag.singh_oneconvergence.com]

Summary

[PATCH 02/31] FreeBSD OFED support for DPDK MLX5 PMD

Extend mlx5dv_get_qp() to return UAR mapping info. This can allow a
process to share its doorbell access with secondary process by re-mmap
the UAR address on the device and make it accessible as a user space
address.

Test Plan

Tested on KVM, ESXi, and HyperV/Azure Hypervisors with FreeBSD 14.0-CURRENT and FreeBSD12.1-STABLE.

iperf
DPDK MLX5 PMD/testpmd