x86 numa: Fix SRAT check for discontig memory

x86 numa: Fix SRAT check for discontig memory

We currently compare the sum of the pages found in the SRAT table to
the address of the highest memory page found via the e820 table to
validate the SRAT.  This is completely bogus if there's any kind of
discontiguous memory, where the sum of the pages could be much smaller
than the address of the highest page.  I think all that's necessary is
to validate that each usable memory range in the e820 is covered by an
SRAT entry.  This might not be the most efficient way to do it, but
there are usually a relatively small number of entries on each side.

Signed-off-by: Alex Williamson <alex.williamson@hp.com>