doc: Add notification information to the documentation
Created by: nicola-mazzucato-arm
This patch adds information in the framework guide for notifications.
Change-Id: I4063eee51e8bafe8076ab2ec53894dc505b38c10 Signed-off-by: Elieva Pignat Elieva.Pignat@arm.com Signed-off-by: Nicola Mazzucato nicola.mazzucato@arm.com