tools: Allow building on Android after noinst_PROGRAMS is not defined any more

Looks like filter-out macro gets silently unhappy about an undefined variable.

Reviewed-by: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
diff --git a/tools/Android.mk b/tools/Android.mk
index 5bda489..99c39b7 100644
--- a/tools/Android.mk
+++ b/tools/Android.mk
@@ -65,6 +65,6 @@
     intel_vga_read \
     intel_vga_write
 
-tools_list := $(filter-out $(skip_tools_list),$(bin_PROGRAMS) $(noinst_PROGRAMS))
+tools_list := $(filter-out $(skip_tools_list),$(bin_PROGRAMS))
 
 $(foreach item,$(tools_list),$(eval $(call add_tool,$(item))))