ion: store a copy of the client name on client creation

Currently, we copy the pointer passed in to ion_client_create without
making a copy of the string itself. This approach is problematic since
it relies on the client keeping the name string in working order.

Change-Id: I62d79c7539b2c857a5a625339d49c9c892e8622d
Signed-off-by: Mitchel Humpherys <mitchelh@codeaurora.org>