fs: eventpoll fix unused variable warning

fs: eventpoll fix unused variable warning

/nvidia/DEV_KERNEL/kernel/fs/eventpoll.c:
In function 'get_epoll_file_task':
/nvidia/DEV_KERNEL/kernel/fs/eventpoll.c:1682:21:
warning: unused variable 'whead' [-Wunused-variable]

Change-Id: I605474bff372c6dae0603caa26b33e1c62f07ab5
Signed-off-by: Philip Rakity <prakity@nvidia.com>
Reviewed-on: http://git-master/r/276697
Reviewed-by: Automatic_Commit_Validation_User
GVS: Gerrit_Virtual_Submit
Reviewed-by: Laxman Dewangan <ldewangan@nvidia.com>
(cherry picked from commit f82a5acac38fdd91ba5e1fa35cf31c67048dfdaf)
Signed-off-by: Ajay Nandakumar <anandakumarm@nvidia.com>