[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/Makefile b/drivers/Makefile
index ea410b6..7fc3f0f 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -13,6 +13,7 @@
 # PnP must come after ACPI since it will eventually need to check if acpi
 # was used and do nothing if so
 obj-$(CONFIG_PNP)		+= pnp/
+obj-$(CONFIG_ARM_AMBA)		+= amba/
 
 # char/ comes before serial/ etc so that the VT console is the boot-time
 # default.