msm: smd: add support for secondary channel table

The primary SMD channel table only supports 64 entries and is currently at
capacity. Since the primary channel table cannot be extended as the SMEM
item ids following the primary table are already reserved for other
usecases, create a secondary channel table by repurposing the unused block
channel table SMEM items.  This extention creates an additional 64 entries
for new SMD channels allowing the system to support a total of 128
channels.

CRs-Fixed: 525753
Change-Id: Ife9c822e46178b4a8bf21c34efabfd7133ed87b0
Signed-off-by: Jeffrey Hugo <jhugo@codeaurora.org>