kfdtest: Style cleanup

Clean up the KFDTest style via CPPLint. Some warnings remain regarding
volatile variables being cast to void*. This is the command used:
cpplint.py --linelength=120
--filter=-readability/multiline_string,-readability/todo,-build/include,-runtime/references

multiline_string is due to using ISA code
todo is to avoid errors that we don't have TODO(username) instead of TODO
include is about including the folder in the header includes
references is regarding non-const references '&' being const or using
pointers. That can be addressed later

Change-Id: I3c6622da0a13dd33ab29b2bfff48be25e763b750

tests/kfdtest/src/PM4Packet.hpp

@@ -112,7 +112,7 @@ class PM4IndirectBufPacket : public PM4Packet {
     // empty constructor, befor using the packet call the init func
     PM4IndirectBufPacket(void) {}
     // this contructor will also init the packet, no need for adittional calls
-    PM4IndirectBufPacket(IndirectBuffer *pIb);
+    explicit PM4IndirectBufPacket(IndirectBuffer *pIb);
 
     virtual ~PM4IndirectBufPacket(void) {}
     // @returns the packet size in bytes