Add new atom to log userspace reboot performance

A first stab at the atom to log.
Actual logic to log will be in the follow up CL.

Test: builds
Bug: 148767783
Change-Id: Id3f81ced73ea708f1dcfbcfd66f554e8daed8ccc
Merged-In: Id3f81ced73ea708f1dcfbcfd66f554e8daed8ccc
(cherry picked from commit 41dd57ee229d808bb401c19cb8533539f0eb42a3)
1 file changed