coresight: increase tmc etr default mem size to 32MB

Increase TMC ETR default memory size to 32MB to allow more debug
information to get collected which will help with crash analysis.

Change-Id: I8c9c22f3015f3bcde268b4b4aa4d952cbf248e8d
Signed-off-by: Pratik Patel <pratikp@codeaurora.org>