staging: 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.

Cc: Colin Cross <ccross@android.com>
Cc: Android Kernel Team <kernel-team@android.com>
Signed-off-by: Mitchel Humpherys <mitchelh@codeaurora.org>
[jstultz: Minor commit subject tweaks]
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>