ANDROID: ensure pages allocated from GCMA are correctly refcounted

When allocating pages from GCMA, they should have the refcount at 1
so that they can be used later for mapping them. Fix refcount
initialization. Note that when pages are returned to GCMA they should
be in the same state, with the caller as the only refcount holder and
no other possible (even temporary) users, which means the page should
not be on any LRU or otherwise accessible by the rest of the kernel.

Bug: 437025819
Bug: 436722327
Change-Id: Ib61e0bce6537ec7d5483d7175e7ba8376c9c7d68
Signed-off-by: Suren Baghdasaryan <surenb@google.com>