target-i386: do not pass MSR_TSC_AUX to KVM ioctls if CPUID bit is not set

target-i386: do not pass MSR_TSC_AUX to KVM ioctls if CPUID bit is not set

KVM does not let you read or write this MSR if the corresponding CPUID
bit is not set.  This in turn causes MSRs that come after MSR_TSC_AUX
to be ignored by KVM_SET_MSRS.

One visible symptom is that s3.flat from kvm-unit-tests fails with
CPUs that do not have RDTSCP, because the SMBASE is not reset to
0x30000 after reset.

Fixes: c9b8f6b6210847b4381c5b2ee172b1c7eb9985d6
Cc: qemu-stable@nongnu.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>