EOF newline added to InverseSize4.

Causing build breakages due to `-Wnewline-eof -Werror` that seems to be
common across Google.

Eigen/src/LU/arch/InverseSize4.h

diff --git a/Eigen/src/LU/arch/InverseSize4.h b/Eigen/src/LU/arch/InverseSize4.h
index a4c9ca2..df0fe0e 100644
--- a/Eigen/src/LU/arch/InverseSize4.h
+++ b/Eigen/src/LU/arch/InverseSize4.h
@@ -345,4 +345,4 @@
 #endif
 } // namespace internal
 } // namespace Eigen
-#endif
\ No newline at end of file
+#endif