Do not export `cb_handle_30_t` from gralloc

it is a private header, add `usage` to `cb_handle_t` instead

Bug: 357912003
Test: presubmit
Change-Id: I0a7fe0e77a2dfee89ecbbef1fe2ba9bbbec6fdd8
Signed-off-by: Roman Kiryanov <rkir@google.com>
5 files changed