libpayload: Export device count in storage interface

FILO can use this as offset to enumerate AHCI and its own IDE
devices together.

Change-Id: I57380e7bd1df6db5c882427e9a34d068f4348fb2
Signed-off-by: Nico Huber <nico.huber@secunet.com>
Reviewed-on: http://review.coreboot.org/1846
Tested-by: build bot (Jenkins)
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>
diff --git a/payloads/libpayload/drivers/storage/storage.c b/payloads/libpayload/drivers/storage/storage.c
index 3e9c375..f623077 100644
--- a/payloads/libpayload/drivers/storage/storage.c
+++ b/payloads/libpayload/drivers/storage/storage.c
@@ -57,6 +57,11 @@
 	return 0;
 }
 
+int storage_device_count(void)
+{
+	return dev_count;
+}
+
 /**
  * Probe for drive with given number
  *