docs(spm): partition runtime model and schedule modes

This patch documents the support for partition runtime models, call
chains and schedule modes in Hafnium SPMC.

Change-Id: I91d5718bb2c21d475499e402f6f27076930336cb
Signed-off-by: Madhukar Pappireddy <madhukar.pappireddy@arm.com>
1 file changed