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/block/Kconfig b/drivers/block/Kconfig
index 6e23af1..fd7a53b 100644
--- a/drivers/block/Kconfig
+++ b/drivers/block/Kconfig
@@ -113,7 +113,7 @@
 
 config BLK_CPQ_DA
 	tristate "Compaq SMART2 support"
-	depends on PCI
+	depends on PCI && VIRT_TO_BUS
 	help
 	  This is the driver for Compaq Smart Array controllers.  Everyone
 	  using these boards should say Y here.  See the file