Remove ALL_GENERATED_SOURCES

ALL_GENERATED_SOURCES contains the generated sources of modules
defined in Make.  They always have a path inside the intermediates
directories.  The only readers of ALL_GENERATED_SOURCES are filtering
for files in the output directories, and will never match anything.

Signed-off-by: Lucas Wei <lucaswei@google.com>
Change-Id: I38c57cc6dad7d762adc001351322c0614e69ed98