clang-tidy: Replace NULL with nullptr

Replaced all instances of NULL with nullptr to improve type safety
and clarity, as nullptr is the modern C++ standard for null pointers.

Tested: Build verified

Change-Id: I1771e207ce2171990fcf55a6f29292f4c70f1284
Signed-off-by: Jayanth Othayoth <ojayanth@gmail.com>
1 file changed