fix: add module_parallel to VPATH in Makefile.Objects

Without this VPATH entry, make cannot locate para_*.cpp source files
for the OBJS_PARALLEL targets, causing build failure:
  No rule to make target 'build/obj/para_world.o'

Author: abacus_fixer

source/Makefile.Objects

@@ -22,6 +22,7 @@ VPATH=./src_global:\
 ./source_base:\
 ./source_base/kernels:\
 ./source_base/module_external:\
+./source_base/module_parallel:\
 ./source_base/module_container/base/core:\
 ./source_base/module_container/ATen/core:\
 ./source_base/module_container/ATen/kernels:\