tty: cyclades: cyz_interrupt is only used for PCI

When CONFIG_PCI is not set, enabling CONFIG_CYZ_INTR has no
practical effect other than generating a warning about an
unused function:

drivers/tty/cyclades.c:1184:20: warning: 'cyz_interrupt' defined but not used [-Wunused-function]
 static irqreturn_t cyz_interrupt(int irq, void *dev_id)

This adds a dependency to avoid that warning.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/Kconfig

@@ -226,7 +226,7 @@ config CYCLADES
 
 config CYZ_INTR
 	bool "Cyclades-Z interrupt mode operation"
-	depends on CYCLADES
+	depends on CYCLADES && PCI
 	help
 	  The Cyclades-Z family of multiport cards allows 2 (two) driver op
 	  modes: polling and interrupt. In polling mode, the driver will check