Revert "host/i386: assume presence of POPCNT"

This reverts commit 45ccdbcb24baf99667997fac5cf60318e5e7db51.
The x86-64 instruction set can now be tuned down to x86-64 v1
or i386 Pentium Pro.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
3 files changed