[Tablegen][DAG]: Fix build breakage when LLVM_ENABLE_DAGISEL_COV=1

LLVM_ENABLE_DAGISEL_COV can be used to instrument DAGISel tablegen
selection code to show which patterns along with Complex patterns were
used when selecting instructions. Unfortunately this is turned off by
default and was broken but never tested.
This required a simple fix (missing new line) to get it to build again.

llvm-svn: 353091