identify_ramdisk_image(): correct typo about return value in comment

identify_ramdisk_image() returns 0 (not -1) if a gzipped ramdisk is found:

if (buf[0] == 037 && ((buf[1] == 0213) || (buf[1] == 0236))) {
printk(KERN_NOTICE
"RAMDISK: Compressed image found at block %d\n",
start_block);
nblocks = 0;
^^^^^^^^^^^
goto done;
}

...

done:
sys_lseek(fd, start_block * BLOCK_SIZE, 0);
kfree(buf);
return nblocks;
^^^^^^^^^^^^^^

Hence correct the typo in the comment, which has existed since the
addition of compressed ramdisk support in 1.3.48.

Signed-off-by: Geert Uytterhoeven <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

init/do_mounts_rd.c

···
 	sys_read(fd, buf, size);
 
 	/*
-	 * If it matches the gzip magic numbers, return -1
+	 * If it matches the gzip magic numbers, return 0
 	 */
 	if (buf[0] == 037 && ((buf[1] == 0213) || (buf[1] == 0236))) {
 		printk(KERN_NOTICE