spl: nand: sunxi: fix second case of modulo by zero error

In the nand_read_buffer() step, the seed is calculated by doing a modulo
by conf->nseeds which is always zero when not using the randomizer (most
of SLC NANDs).

This situation turns out to lead to a run time freeze with certain
toolchains.

Derive this seed only when the randomizer is enabled (and conf->nseeds
logically not zero), exactly like what has been done before with an
identical situation, see commit ea3f750c73 ("nand: sunxi: Fix modulo
by zero error").

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Acked-by: Boris Brezillon <boris.brezillon@bootlin.com>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>

drivers/mtd/nand/sunxi_nand_spl.c

@@ -475,11 +475,12 @@ static int nand_detect_config(struct nfc_config *conf, u32 offs, void *dest)
 static int nand_read_buffer(struct nfc_config *conf, uint32_t offs,
 			    unsigned int size, void *dest)
 {
-	int first_seed, page, ret;
+	int first_seed = 0, page, ret;
 
 	size = ALIGN(size, conf->page_size);
 	page = offs / conf->page_size;
-	first_seed = page % conf->nseeds;
+	if (conf->randomize)
+		first_seed = page % conf->nseeds;
 
 	for (; size; size -= conf->page_size) {
 		if (nand_load_page(conf, offs))