[ARM] Move AMBA bus code to drivers/amba/

Make the AMBA bus code visible to other architectures.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/drivers/amba/Makefile b/drivers/amba/Makefile
new file mode 100644
index 0000000..40fe740
--- /dev/null
+++ b/drivers/amba/Makefile
@@ -0,0 +1,2 @@
+obj-y		+= bus.o
+