build: fix meson build on FreeBSD

build: fix meson build on FreeBSD

A number of drivers have dependencies on libraries which
are only built on Linux, and so they need to be disabled
on FreeBSD. Rather than basing the disabling on OS, in
each case we base the building of the library on the
presence of the required dependency.

Fixes: 50385c106021 ("net/ifc: add to meson build")
Fixes: 4e9c73e96e83 ("net/netvsc: add Hyper-V network device")
Fixes: 5936aa3a39b9 ("net/vhost: add to meson build")
Fixes: 3298fa4853b8 ("raw/dpaa2_cmdif: introduce DPAA2 command interface driver")
Fixes: b1ee472fed58 ("raw/dpaa2_qdma: introduce the DPAA2 QDMA driver")
Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>