apbuart: Depend upon sparc.

It absolutely needs to be able to get at pdev_archdata members
which are sparc specific.

Signed-off-by: David S. Miller <davem@davemloft.net>
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
index e1aee37..80484af 100644
--- a/drivers/tty/serial/Kconfig
+++ b/drivers/tty/serial/Kconfig
@@ -1506,7 +1506,7 @@
 
 config SERIAL_GRLIB_GAISLER_APBUART
 	tristate "GRLIB APBUART serial support"
-	depends on OF
+	depends on OF && SPARC
 	select SERIAL_CORE
 	---help---
 	Add support for the GRLIB APBUART serial port.