PowerCap: Fix build error with option -Werror=format-security

Fix compile error with gcc option: -Werror=format-security for
dev_set_name(&control_type->dev, name).

Changed to dev_set_name(&control_type->dev, "%s", name).

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>