omap_rev_string: output to stdout

* avoid potential buffer overflows
* allow SPL-build not to output "Texas Instruments Revision detection unimplemented"

Signed-off-by: Andreas Müller <schnitzeltony@gmx.de>
Signed-off-by: Tom Rini <trini@ti.com>
diff --git a/arch/arm/include/asm/omap_common.h b/arch/arm/include/asm/omap_common.h
index efbf646..34bec45 100644
--- a/arch/arm/include/asm/omap_common.h
+++ b/arch/arm/include/asm/omap_common.h
@@ -91,7 +91,7 @@
 
 /* SPL common function s*/
 void spl_parse_image_header(const struct image_header *header);
-void omap_rev_string(char *omap_rev_string);
+void omap_rev_string(void);
 
 /* NAND SPL functions */
 void spl_nand_load_image(void);