Introduce CONFIG_VIRT_TO_BUS

Make some offending drivers depend on it and set CONFIG_ARCH_NO_VIRT_TO_BUS
for ppc64 so that we don't build those drivers.

This gets PowerPC allmodconfig and allyesconfig much closer to building.

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Al Viro <viro@ftp.linux.org.uk>
Acked-by: David Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/net/wan/Kconfig b/drivers/net/wan/Kconfig
index 4fc8681..a3df09e 100644
--- a/drivers/net/wan/Kconfig
+++ b/drivers/net/wan/Kconfig
@@ -61,7 +61,7 @@
 #
 config LANMEDIA
 	tristate "LanMedia Corp. SSI/V.35, T1/E1, HSSI, T3 boards"
-	depends on PCI
+	depends on PCI && VIRT_TO_BUS
 	---help---
 	  Driver for the following Lan Media family of serial boards: