mesa-dri: Disable some arm drivers
We don't have any hardware or driver capable of running the freedreno driver
so disable it.
Our VC4 support don't work with mesa so disable it too.
Reviewed by: zeising (x11@)
Approved by: zeising (x11@)
Differential Revision: https://reviews.freebsd.org/D25093
Update the Mesa ports to 17.2.2
Mesa supports both llvm40 and llvm50. The former remains the default as it's
what the OpenCL ports currently require and it's available on more platforms.