Revert "Build libcamera from source (3/3)"

Provide prebuilt froyo libcamera.so (TARGET_PREBUILT_LIBCAMERA)

This reverts commit b1e4a18ead321d1015899b1038a4a730897f3536.

Change-Id: I70b3124933836748c4b541dd3b4f3ca2aa482f96