Update modulemaps for Analysis/VecFuncs.def.

Avoid a warning while building modular LLVM due to a new
textual header missing in the modulemap:

TargetLibraryInfo.cpp:1485:6: warning: missing submodule
  'LLVM_Analysis.VecFuncs' [-Wincomplete-umbrella]

Added VecFuncs.def as a textual header in LLVM_Analysis.

llvm-svn: 358021