[logd] Modernize codebase by replacing NULL with nullptr

Fixes -Wzero-as-null-pointer-constant warning.

Test: m
Bug: 68236239
Change-Id: I15ccb9cfc9967dae4320d9690f5097bc2f7d5bfe
11 files changed
tree: 7b392b3764946fed93d3dcb8ee4a1d8bb7269ab3
  1. liblog/
  2. logcat/
  3. logd/
  4. logwrapper/