can: fix build dependency

Arnd Bergmann's patch [1] fixed the build dependency problem introduced by
bugfix commit cb2dc6d286 ("can: Kconfig: select CAN driver infrastructure
by default"). This ended up as commit 6abd4577bc ("can: fix build
dependency"), but I broke Arnd's fix by removing a dependency that we
thought was superfluous.

[1] https://lore.kernel.org/all/[email protected]/

Meanwhile the problem was also found by intel's kernel test robot,
complaining about undefined symbols:

| ERROR: modpost: "m_can_class_unregister" [drivers/net/can/m_can/m_can_platform.ko] undefined!
| ERROR: modpost: "m_can_class_free_dev" [drivers/net/can/m_can/m_can_platform.ko] undefined!
| ERROR: modpost: "m_can_class_allocate_dev" [drivers/net/can/m_can/m_can_platform.ko] undefined!
| ERROR: modpost: "m_can_class_get_clocks" [drivers/net/can/m_can/m_can_platform.ko] undefined!
| ERROR: modpost: "m_can_class_register" [drivers/net/can/m_can/m_can_platform.ko] undefined!

To fix this problem, add the missing dependency again.

Cc: Vincent Mailhol <[email protected]>
Reported-by: kernel test robot <[email protected]>
Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]/
Reported-by: kernel test robot <[email protected]>
Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]/
Reported-by: Arnd Bergmann <[email protected]>
Closes: https://lore.kernel.org/all/[email protected]/
Fixes: 6abd4577bc ("can: fix build dependency")
Fixes: cb2dc6d286 ("can: Kconfig: select CAN driver infrastructure by default")
Acked-by: Vincent Mailhol <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Marc Kleine-Budde <[email protected]>

drivers/net/can/Kconfig

@@ -17,7 +17,7 @@ menuconfig CAN_DEV
 	  virtual ones. If you own such devices or plan to use the virtual CAN
 	  interfaces to develop applications, say Y here.
 
-if CAN_DEV
+if CAN_DEV && CAN
 
 config CAN_VCAN
 	tristate "Virtual Local CAN Interface (vcan)"