Android.mk: Fix missing \ from recent llvm change

Building w/ AOSP, I was hitting the following error:
external/mesa3d/src/amd/Android.common.mk:95: error: missing separator.

Which was due to the changes to mesa-build-with-llvm  missing
a line continuation.

Fixes: 96b592696f
Signed-off-by: John Stultz <john.stultz@linaro.org>

Android.mk

@@ -97,7 +97,7 @@ endif
 define mesa-build-with-llvm
   $(if $(filter $(MESA_ANDROID_MAJOR_VERSION), 4 5 6 7), \
     $(warning Unsupported LLVM version in Android $(MESA_ANDROID_MAJOR_VERSION)),) \
-  $(eval LOCAL_CFLAGS += -DLLVM_AVAILABLE -DMESA_LLVM_VERSION_STRING=\"3.9\")
+  $(eval LOCAL_CFLAGS += -DLLVM_AVAILABLE -DMESA_LLVM_VERSION_STRING=\"3.9\") \
   $(eval LOCAL_SHARED_LIBRARIES += libLLVM)
 endef