spl: add newline in debug output

With debug enabled, SPL output following these debug prints is on the
same line and it is hard to read. Fix it.

Signed-off-by: Anatolij Gustschin <agust@denx.de>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/common/spl/spl.c b/common/spl/spl.c
index 8b219ba..ce9819e 100644
--- a/common/spl/spl.c
+++ b/common/spl/spl.c
@@ -158,7 +158,7 @@
 			spl_image->load_addr, spl_image->size);
 #else
 		/* LEGACY image not supported */
-		debug("Legacy boot image support not enabled, proceeding to other boot methods");
+		debug("Legacy boot image support not enabled, proceeding to other boot methods\n");
 		return -EINVAL;
 #endif
 	} else {
@@ -196,7 +196,7 @@
 		spl_set_header_raw_uboot(spl_image);
 #else
 		/* RAW image not supported, proceed to other boot methods. */
-		debug("Raw boot image support not enabled, proceeding to other boot methods");
+		debug("Raw boot image support not enabled, proceeding to other boot methods\n");
 		return -EINVAL;
 #endif
 	}