Fix Test/hlsl.namespace.frag test case
Before this change, the example is rejected by DXC:
$ dxc -T ps_6_0 hlsl.namespace.frag
hlsl.namespace.frag:22:73: error: call to non-static member function
without an object argument
return N1::getVec() + N2::getVec() + N2::N3::getVec() + N2::N3::C1::getVec() * N2::gf;
~~~~~~~~~~~~^~~~~~
The call to the class member function requires an object, or we ned to
make the function static. This update makes the function static.
This also fixes SPIR-V validation: without this change the call
to that getVec does not have enough arguments:
error: line 69: OpFunctionCall Function <id>'s parameter count does not
match the argument count.
%43 = OpFunctionCall %v4float %N2__N3__C1__getVec_