staging: vchiq_debugfs: Fix build if CONFIG_DEBUG_FS is not set

Commit 42a2f666 ("staging: vc04_services: Move global g_state to
vchiq_state") adds a parameter to vchiq_debugfs_init, but leaves the
dummy implementation in the !CONFIG_DEBUG_FS case untouched, causing a
compile time error.

Fixes: c3552ab1

 ("staging: vchiq_debugfs: Fix NPD in vchiq_dump_state")
Signed-off-by: Bernhard Rosenkränzer <bero@baylibre.com>
Reviewed-by: Stefan Wahren <wahrenst@gmx.net>
Link: https://lore.kernel.org/r/20240627124419.2498642-1-bero@baylibre.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>