board: copper: Increase QSECOM heap to 6MB

QSECOM requires a total of 6MB for concurrent
use. The memory is divided between HDCP (3M),
Payready (2M), and QSECOM (1MB).

Increase the QSECOM ION heap from 1MB to 6MB.

Change-Id: I98bef75832e8a774174b1dcd2a18a7d675284ba7
Signed-off-by: Olav Haugan <ohaugan@codeaurora.org>