NdcDispatcher - fix bugprone-macro-parentheses warnings

Fixes:
  system/netd/server/NdcDispatcher.cpp:55:46: warning: macro argument should be enclosed in parentheses [bugprone-macro-parentheses]
  system/netd/server/NdcDispatcher.cpp:57:13: ...
  system/netd/server/NdcDispatcher.cpp:64:47: ...
  system/netd/server/NdcDispatcher.cpp:66:13: ...

Test: builds
Bug: 153035880
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Change-Id: I50f89e8b2e90c623c5473f543e38e16ac973a3c4