scsi: Add function and env var to report number of scsi drives

Add a new function to find out the number of available SCSI disks. Also
set the 'scsidevs' environment variable after each scan.

Signed-off-by: Stefan Reinauer <reinauer@chromium.org>
Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/common/cmd_scsi.c b/common/cmd_scsi.c
index 31ea788..9bd8ec9 100644
--- a/common/cmd_scsi.c
+++ b/common/cmd_scsi.c
@@ -184,6 +184,14 @@
 		scsi_curr_dev=0;
 	else
 		scsi_curr_dev = -1;
+
+	printf("Found %d device(s).\n", scsi_max_devs);
+	setenv_ulong("scsidevs", scsi_max_devs);
+}
+
+int scsi_get_disk_count(void)
+{
+	return scsi_max_devs;
 }
 
 #ifdef CONFIG_PCI