lib: Remove redundant IPI types

We just need to distinguish only between FENCE and non FENCE related
IPIs as all of the fence related requests are handled via fifo now.

Remove the unnecessary IPI types related to individual fence types.

Signed-off-by: Atish Patra <atish.patra@wdc.com>
Reviewed-by: Anup Patel <anup.patel@wdc.com>