mtd: rawnand: stm32_fmc2: fix a buffer overflow

This patch solves following static checker warning:
drivers/mtd/nand/raw/stm32_fmc2_nand.c:350 stm32_fmc2_nfc_select_chip()
error: buffer overflow 'nfc->data_phys_addr' 2 <= 2

The CS value can only be 0 or 1.

Signed-off-by: Christophe Kerello <christophe.kerello@st.com>
Fixes: 2cd457f328 ("mtd: rawnand: stm32_fmc2: add STM32 FMC2 NAND flash controller driver")
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/1595325127-32693-1-git-send-email-christophe.kerello@st.com

drivers/mtd/nand/raw/stm32_fmc2_nand.c

@@ -1763,7 +1763,7 @@ static int stm32_fmc2_nfc_parse_child(struct stm32_fmc2_nfc *nfc,
 			return ret;
 		}
 
-		if (cs > FMC2_MAX_CE) {
+		if (cs >= FMC2_MAX_CE) {
 			dev_err(nfc->dev, "invalid reg value: %d\n", cs);
 			return -EINVAL;
 		}