haven: hh_msgq: add MSGQ label for display

Display uses RM owned MSGQ for lending mem and irq res handles. In
addition, display may need to communicate custom data between the VMs
based on the value added display features that need to be supported
while the trusted VM applications are active. This change introduces
the MSGQ dedicated for display to establish the communication channel.

Change-Id: I8d07a3eb8591364f245c37a947a9ba5457c46efb
Signed-off-by: Jeykumar Sankaran <jsanka@codeaurora.org>