msm: kgsl: Update the mailbox message and length for ACD QMP message

Update the message string and adjust the message length as mailbox
controller expects 4-byte aligned buffer.

Change-Id: Ifc357a27b63d1d04f5d0149f637814e5d35262f4
Signed-off-by: Mohammed Mirza Mandayappurath Manzoor <mmandaya@codeaurora.org>