KVM: x86: Fix CPUID function for word 6 (80000001_ECX)

The function for CPUID 80000001 ECX is set to 0xc0000001. Set it to
0x80000001.

Signed-off-by: Janakarajan Natarajan <Janakarajan.Natarajan@amd.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Reviewed-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Reviewed-by: Borislav Petkov <bp@suse.de>
Fixes: d6321d49 ("KVM: x86: generalize guest_cpuid_has_ helpers")
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>