torture: Enable clocksource watchdog with "tsc=watchdog"

[ Upstream commit 877a0e83 ]

This commit tests the "tsc=watchdog" kernel boot parameter when running
the clocksourcewd torture tests.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Stable-dep-of: f2655ac2 ("clocksource: Fix brown-bag boolean thinko in cs_watchdog_read()")
Signed-off-by: Sasha Levin <sashal@kernel.org>