Remove extra '}' from panda/mathutil/CMakeLists.txt that was causing linking errors.

panda/src/mathutil/CMakeLists.txt

@@ -62,7 +62,7 @@ set(P3MATHUTIL_SOURCES
 
 composite_sources(p3mathutil P3MATHUTIL_SOURCES)
 add_library(p3mathutil ${P3MATHUTIL_HEADERS} ${P3MATHUTIL_SOURCES})
-target_link_libraries(p3mathutil p3event ${FFTW2_LIBRARY_DIR}})
+target_link_libraries(p3mathutil p3event ${FFTW2_LIBRARY_DIR})
 target_interrogate(p3mathutil ALL)
 
 #begin test_bin_target