ARC: [*defconfig] Reenable soft lock-up detector

Commit 92e5aae4 "kernel/watchdog: split up config options"
introduced SOFTLOCKUP_DETECTOR which selects LOCKUP_DETECTOR
instead of the latter to be selected itself.

We need to adjust our defconfigs accordingly.

Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>