test: use DUMMY_DEV when creating dummy devices.
test: use DUMMY_DEV when creating dummy devices.

Test steps using the 'dummy' kernel module use be marked by the DUMMY_DEV
prerequisite. When the 'dummy' kernel module is not present, such steps
are skipped properly.

Signed-off-by: Emmanuel Roullit <e51ad7dcb99c77ecf30f537962c562ac80636eba@gmail.com>

eroullit/dabba,eroullit/dabba,eroullit/dabba,eroullit/dabba