sim: Remove DelayFunction
sim: Remove DelayFunction

`DelayFunction` is unused.

Change-Id: I28aa756054c9b121fe4cfa65c393366f26ccb128
Signed-off-by: Sean Wilson <6fa6ac529d4ad9d96bb88f2c1f1b9723eba9acbe@wisc.edu>
Reviewed-on: https://gem5-review.googlesource.com/3741
Reviewed-by: Andreas Sandberg <c9f5686ee5bd561c93f9de79681eee75bfa7f36e@arm.com>
Reviewed-by: Jason Lowe-Power <68c46a606457643eab92053c1c05574abb26f861@lowepower.com>
Maintainer: Andreas Sandberg <c9f5686ee5bd561c93f9de79681eee75bfa7f36e@arm.com>

TUD-OS/gem5-dtu,sobercoder/gem5,sobercoder/gem5,TUD-OS/gem5-dtu,TUD-OS/gem5-dtu,rallylee/gem5,sobercoder/gem5,gem5/gem5,rallylee/gem5,sobercoder/gem5,gem5/gem5,gem5/gem5,TUD-OS/gem5-dtu,sobercoder/gem5,TUD-OS/gem5-dtu,gem5/gem5,rallylee/gem5,sobercoder/gem5,TUD-OS/gem5-dtu,rallylee/gem5,rallylee/gem5,sobercoder/gem5,rallylee/gem5,gem5/gem5,rallylee/gem5,gem5/gem5,gem5/gem5,TUD-OS/gem5-dtu