init: use pr_cont() when displaying rotator during ramdisk loading.

Otherwise each individual rotator char would be printed in a new line:

(...)
[    0.642350] -
[    0.644374] |
[    0.646367] -
(...)
Signed-off-by: Nicolas Schichan <nicolas.schichan@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

init/do_mounts_rd.c

@@ -272,7 +272,7 @@ int __init rd_load_image(char *from)
 		sys_write(out_fd, buf, BLOCK_SIZE);
 #if !defined(CONFIG_S390)
 		if (!(i % 16)) {
-			printk("%c\b", rotator[rotate & 0x3]);
+			pr_cont("%c\b", rotator[rotate & 0x3]);
 			rotate++;
 		}
 #endif