ANDROID: sched: Initialize arguments of android_rvh_replace_next_task_fair

android_rvh_replace_next_task_fair() hooks allows vendor modules to
replace the next task selected by the CFS. There are two cases in
how this hook is called.

1. When the previous task is also a CFS task. In this case, the
task_struct (p) and sched_entity (se) arguments passed to this
hook are valid and point to the task selected by the CFS.

2. When the previous task is not a CFS task. In this case, the
arguments passed to this hook are not initialized.

Initialize these arguments to NULL which allows vendor modules
when not to peek into the selected task by CFS.

Bug: 184695001
Fixes: 09e27d4f ("ANDROID: vendor_hooks: Add hooks for scheduler")
Change-Id: Ib51dacb607663a2a6434e49198f59b36fb8c9312
Signed-off-by: Pavankumar Kondeti <quic_pkondeti@quicinc.com>
Signed-off-by: Shaleen Agrawal <shalagra@codeaurora.org>