ia64: remove support for machvecs

The only thing remaining of the machvecs is a few checks if we are
running on an SGI UV system.  Replace those with the existing
is_uv_system() check that has been rewritten to simply check the
OEM ID directly.

That leaves us with a generic kernel that is as fast as the previous
DIG/ZX1/UV kernels, but can support all hardware.  Support for UV
and the HP SBA IOMMU is now optional based on new config options.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lkml.kernel.org/r/20190813072514.23299-27-hch@lst.de


Signed-off-by: Tony Luck <tony.luck@intel.com>