vtd: consolidate VT-d quirks into a single file quirks.c

vtd: consolidate VT-d quirks into a single file quirks.c

Consolidate VT-d quirks into a single file - quirks.c.  This includes
quirks to workaround OEM BIOS issue with VT-d enabling in IGD, Cantiga
VT-d buffer flush issue, Cantiga IGD Vt-d low power related errata,
and a quirk to workaround issues related to wifi direct assignment.

Signed-off-by: Allen Kay <allen.m.kay@intel.com>
Reviewed-by: Jan Beulich <JBeulich@novell.com>