Improve finding half.hpp

[trixirt]

On Fedora half.hpp is installed to the system dir /usr/include. There is no cmake package, so finding the half cmake package will always fail. The source looks for half with #include <half/half.h> The use of half/ makes it impossible to find and use the system location.

So look for the half.hpp path and add add that to the include_directories.

Use this sed script to programatically change the uses of #include <half/half.h>

for f in find . -type f -name '*.hpp' -o -name '*.cpp' ; do sed -i -e 's@#include <half/half.hpp>@#include <half.hpp>@' $f done

This covers this issue https://github.com/ROCm/rpp/issues/292