arm64: defconfig: Enable CONFIG_HH_MEM_NOTIFIER

Enable the Haven memory notification framework to multiplex
memory resource notifications amongst clients for memory
resources on Lahaina and the trusted VM.

Change-Id: I4450d78ea58e01c57fdd65e734ceee7f91b1e4c8
Signed-off-by: Isaac J. Manjarres <isaacm@codeaurora.org>