block: fix rootwait= again

The previous rootwait fix added an -EINVAL return to a completely
bogus superflous branch, fix this.

Fixes: 1341c7d2ccf4 ("block: fix rootwait=")
Reported-by: Mark Brown <[e-mail]>
Signed-off-by: Christoph Hellwig <[e-mail]>
Tested-by: Fabio Estevam <[e-mail]>
Tested-by: Marek Szyprowski <[e-mail]>
Tested-by: Mark Brown <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Jens Axboe <[e-mail]>

block/early-lookup.c

···
 	*p = '\0';
 	*devt = blk_lookup_devt(s, part);
 	if (*devt)
-		return -ENODEV;
+		return 0;
 
 	/* try disk name without p<part number> */
 	if (p < s + 2 || !isdigit(p[-2]) || p[-1] != 'p')