kvm: Add KVM_GET_EMULATED_CPUID

kvm: Add KVM_GET_EMULATED_CPUID

Add a kvm ioctl which states which system functionality kvm emulates.
The format used is that of CPUID and we return the corresponding CPUID
bits set for which we do emulate functionality.

Make sure ->padding is being passed on clean from userspace so that we
can use it for something in the future, after the ioctl gets cast in
stone.

s/kvm_dev_ioctl_get_supported_cpuid/kvm_dev_ioctl_get_cpuid/ while at
it.

Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
(cherry picked from commit 9c15bb1d0a8411f9bb3395d21d5309bde7da0c1c)
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>