intel: replace large stack buffer with heap allocation

intel: replace large stack buffer with heap allocation

For now, this keeps the "100 bytes" allocation; we can try to figure out
the correct size as a follow up.

Suggested-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Signed-off-by: Eric Engestrom <eric.engestrom@intel.com>
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>