Mark media.bufferpool2 and media.c2 as double-loadable

LL-NDK(libmediandk) has the dependency on
"android.hardware.media.bufferpool2" and "android.hardware.media.c2".

Dependencies:
libmediandk -> libstagefright -> libsfplugin_ccodec
-> android.hardware.media.c2-V1-ndk
libmediandk -> libstagefright -> libsfplugin_ccodec
-> libcodec2_client -> libstagefright_bufferpool@
-> android.hardware.media.bufferpool2-V1-ndk

Bug: 251850069
Test: builds
Merged-In: I89aa17b8f1db9393d506edd9f242112cd11a05ec
Change-Id: I89aa17b8f1db9393d506edd9f242112cd11a05ec