powerpc/sched: Cleanup vcpu_is_preempted()

No functional change in this patch. A helper is added to find if
vcpu is dispatched by hypervisor. Use that instead of opencoding.
Also clarify some of the comments.

Signed-off-by: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20231114071219.198222-1-aneesh.kumar@linux.ibm.com
This commit is contained in:
Aneesh Kumar K.V 2023-11-14 12:42:19 +05:30 • committed by Michael Ellerman
commit 6f4b7052da