i965/chv: Display proper branding

i965/chv: Display proper branding

"Braswell" is a Cherryview based *thing*. It unfortunately requires extra
information to determine its marketing name. Unlike all previous products, and
hopefully all future ones, there is no unique 1:1 mapping of PCI device ID to
brand string.

I put up a fight about adding any complexity to our GL renderer string code for
a very long time. However, a wise man made a comment to me that I couldn't argue
with: if a user installs Windows on their hardware, the brand string should be
the same as what we display in Linux. The Windows driver apparently does this
check, so we should too.

Note that I did manage to find a good use for this info anyway in the compute
shader thread counts.

v2: memcpy instead of strncpy, and some minor changes (Matt)

Signed-off-by: Ben Widawsky <benjamin.widawsky@intel.com>
Reviewed-by: Matt Turner <mattst88@gmail.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com