KVM: SVM: move feature detection to hardware setup code

By moving the SVM feature detection from the each_cpu code to the hardware
setup code it runs only once. As an additional advance the feature check is now
available earlier in the module setup process.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>