Fix MathTransforms library dependencies

[bondhugula]

Summary

The dependencies were set up improperly likely due to past code
locations. MathTransforms shouldn't depend on VectorUtils which add a
whole bunch of additional dependencies; it instead depends on the SCF
dialect.

mlir/lib/Dialect/Math/Transforms/CMakeLists.txt

 add_mlir_dialect_library(MLIRMathTransforms
   AlgebraicSimplification.cpp
   ExpandPatterns.cpp
   PolynomialApproximation.cpp
 
   ADDITIONAL_HEADER_DIRS
   ${MLIR_MAIN_INCLUDE_DIR}/mlir/Dialect/Math/Transforms
 
   LINK_LIBS PUBLIC
   MLIRArithDialect
-  MLIRDialectUtils  
+  MLIRDialectUtils
   MLIRIR
   MLIRMathDialect
+  MLIRSCFDialect
   MLIRPass
   MLIRTransforms
   MLIRX86VectorDialect
   MLIRVectorDialect
-  MLIRVectorUtils
   )