microcode/amd: call svm_host_osvw_init() in common code

microcode/amd: call svm_host_osvw_init() in common code

Introduce a vendor hook, .end_update_percpu, for svm_host_osvw_init().
The hook function is called on each cpu after loading an update.
It is a preparation for spliting out apply_microcode() from
cpu_request_microcode().

Note that svm_host_osvm_init() should be called regardless of the
result of loading an update.

Signed-off-by: Chao Gao <chao.gao@intel.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>