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: Ia40d9435ab57651ec6d13d5408cf69130043fa79
Signed-off-by: Jayanth Othayoth <ojayanth@gmail.com>
diff --git a/ipmisensor.cpp b/ipmisensor.cpp
index 55e4914..b66c585 100644
--- a/ipmisensor.cpp
+++ b/ipmisensor.cpp
@@ -244,7 +244,7 @@
     {0x12, 0x04, set_sensor_dbus_state_system_event, "setValue", "", ""},
     {0xCA, 0x00, set_sensor_dbus_state_simple, "setValue", "Disabled", ""},
     {0xCA, 0x01, set_sensor_dbus_state_simple, "setValue", "Enabled", ""},
-    {0xFF, 0xFF, NULL, "", "", ""}};
+    {0xFF, 0xFF, nullptr, "", "", ""}};
 
 void reportSensorEventAssert(const sensorRES_t* pRec, int index)
 {