Generate linker config with packaged items.

Previously, we gather all deps without checking if a dep is actually one
of packaged items (CopyDepsToZip contents)

For example, following items shouldn't be listed.

provideLibs: "platform-mainline-sdk_libartpalette-system@current.so"
provideLibs: "platform-mainline-sdk_liblog@current.so"
provideLibs: "runtime-module-sdk_libc@current.so"
provideLibs: "runtime-module-sdk_libdl@current.so"
provideLibs: "runtime-module-sdk_libdl_android@current.so"
provideLibs: "runtime-module-sdk_libm@current.so"

Now, we gather only those modules contributing CopyDepsToZip to generate
linker config for android_system_image.

Test: m nothing
Test: m microdroid
Test: conv_linker_config print -s
    .../microdroid/android_common/root/system/etc/linker.config.pb
    shouldn't list sdk members.
Change-Id: Ife5d2193ab59970367d10e196aaaa922c6582862