common: spl: Add spl sata boot support

Add spl_sata to read a fat partition from a bootable SATA
drive.

Signed-off-by: Dan Murphy <dmurphy@ti.com>
Reviewed-by: Roger Quadros <rogerq@ti.com>
diff --git a/common/cmd_scsi.c b/common/cmd_scsi.c
index 7b97dc9..b3f7687 100644
--- a/common/cmd_scsi.c
+++ b/common/cmd_scsi.c
@@ -168,7 +168,9 @@
 		scsi_curr_dev = -1;
 
 	printf("Found %d device(s).\n", scsi_max_devs);
+#ifndef CONFIG_SPL_BUILD
 	setenv_ulong("scsidevs", scsi_max_devs);
+#endif
 }
 
 int scsi_get_disk_count(void)