op: cosolidate all op functions into op_fns.c

Now each op functions are quite simple and share a lot of commonalities,
it is easier to maintain moving them into a single source file.

src/mpi/coll/op/Makefile.mk

@@ -6,18 +6,5 @@
 mpi_core_sources += \
     src/mpi/coll/op/op_impl.c        \
     src/mpi/coll/op/oputil.c         \
-    src/mpi/coll/op/opsum.c          \
-    src/mpi/coll/op/opmax.c          \
-    src/mpi/coll/op/opmin.c          \
-    src/mpi/coll/op/opband.c         \
-    src/mpi/coll/op/opbor.c          \
-    src/mpi/coll/op/opbxor.c         \
-    src/mpi/coll/op/opland.c         \
-    src/mpi/coll/op/oplor.c          \
-    src/mpi/coll/op/oplxor.c         \
-    src/mpi/coll/op/opprod.c         \
-    src/mpi/coll/op/opminloc.c       \
-    src/mpi/coll/op/opmaxloc.c       \
-    src/mpi/coll/op/opno_op.c        \
-    src/mpi/coll/op/opreplace.c      \
+    src/mpi/coll/op/op_fns.c         \
     src/mpi/coll/op/opequal.c