Removing some left over places where implicit instantiations were being ignored in headers

cpp/include/raft/distance/fused_distance_nn.cuh

@@ -15,10 +15,4 @@
  */
 #pragma once
 
-#ifndef RAFT_EXPLICIT_INSTANTIATE_ONLY
-#include "fused_distance_nn-inl.cuh"
-#endif
-
-#ifdef RAFT_COMPILED
-#include "fused_distance_nn-ext.cuh"
-#endif
+#include "fused_distance_nn-inl.cuh"

cpp/include/raft/linalg/detail/coalesced_reduction.cuh

@@ -16,11 +16,4 @@
 
 #pragma once
 
-// Always include inline definitions of coalesced reduction, because we do not
-// force explicit instantion.
 #include "coalesced_reduction-inl.cuh"
-
-// Do include the extern template instantiations when possible.
-#ifdef RAFT_COMPILED
-#include "coalesced_reduction-ext.cuh"
-#endif