staging: android: ion: Do not assign heap IDs as heaps register

Some implementations of ION have predetermined heap IDs,
and as such, do not support dynamically assigned heap IDs.
Thus, do not assign heap IDs when the heaps register, so
as to respect their predetermined heap IDs.

Change-Id: I73fa688577da2a249cbe9b405356fc7cf5cb165a
Signed-off-by: Isaac J. Manjarres <isaacm@codeaurora.org>