torture: Allow scenario-specific Kconfig options to override CFcommon

torture: Allow scenario-specific Kconfig options to override CFcommon

This commit applies config_override_param() to allow scenario-specific
Kconfig options to override those in CFcommon.  This in turn will allow
additional Kconfig options to be placed in CFcommon, for example, an
option common to all but a few scenario can be placed in CFcommon and
then overridden in those few scenarios.  Plus this change saves one
whole line of code.

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