torture: Apply CONFIG_KCSAN_STRICT to kvm.sh --kcsan argument

Currently, the --kcsan argument to kvm.sh applies a laundry list of
Kconfig options.  Now that KCSAN provides the CONFIG_KCSAN_STRICT Kconfig
option, this commit reduces the laundry list to this one option.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>