After using get_vm_from_vmid(), vm pointer is always not NULL. But there are still many NULL pointer checks.
This commit replaced the NULL vm pointer check with a validation check which checks the vm status.
In addition, NULL check for pointer returned by get_sos_vm() and get_vm_config() is removed.
Tracked-On: #2520
Signed-off-by: Yan, Like <like.yan@intel.com>
Acked-by: Eddie Dong <eddie.dong@intel.com>