base: unix: remove unsafe in duration_to_timespec()
base: unix: remove unsafe in duration_to_timespec()

This function just initializes a simple struct with two elements; it
does not need to use `unsafe`.

BUG=None
TEST=cargo test -p base

Change-Id: I6f7db5df29cb8a181d2f69ea4cede1ad8be12234
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosvm/+/3652894
Tested-by: kokoro <2ac7b1f3fa578934c95181d4272be0d3bca00121@google.com>
Reviewed-by: Anton Romanov <7c8c28e1283c1d87f2c3df4d6b5c74b6ae02bcd9@google.com>
Commit-Queue: Daniel Verkamp <72bc170b46ec491f7bdd4359a1c0bfed274de40c@chromium.org>

google/crosvm,google/crosvm,google/crosvm,google/crosvm