test.cmake: remove unneeded target link libraries

aom_av1_rc adds aom as a target link library, aom_gmock (which adds
aom_gtest) is unused, as is webm. Fixes a warning when linking on macOS:
ld: warning: ignoring duplicate libraries: 'libaom.a', 'libaom_gtest.a'

Change-Id: I6d881bade3f5d32fc971c3493cdd106069e92be3

test/test.cmake

diff --git a/test/test.cmake b/test/test.cmake
index 2631c9f..da14468 100644
--- a/test/test.cmake
+++ b/test/test.cmake
@@ -638,8 +638,7 @@
      AND NOT BUILD_SHARED_LIBS
      AND NOT CONFIG_REALTIME_ONLY)
     add_executable(test_aom_rc ${AOM_RC_TEST_SOURCES})
-    target_link_libraries(test_aom_rc ${AOM_LIB_LINK_TYPE} aom aom_av1_rc
-                          aom_gtest aom_gmock webm)
+    target_link_libraries(test_aom_rc ${AOM_LIB_LINK_TYPE} aom_av1_rc aom_gtest)
     set_property(TARGET test_aom_rc PROPERTY FOLDER ${AOM_IDE_TEST_FOLDER})
     list(APPEND AOM_APP_TARGETS test_aom_rc)
   endif()