sched: hmp: Change small task packing defaults for all platforms

sched: hmp: Change small task packing defaults for all platforms

All platforms other than TC2 default to enabling packing. Since TC2
shows no performance or energy degradation with this feature enabled
make it default enabled the same as everyone else.
Likewise, vendors have been including TC2 support in multi-machine
kernel builds so they expect the default thresholds to remain the
same when the TC2 #ifdef is removed.

Signed-off-by: Chris Redpath <chris.redpath@arm.com>
Signed-off-by: Jon Medhurst <tixy@linaro.org>