MIPS: Fix gen_nand probe structures contents

This platform didn't properly fill nr_chips in gen_nand
registration and therefore depended on gen_nand bug fixed by commit
81cbb0b177 ("mtd: gen_nand: fix support for
multiple chips")
    
Signed-off-by: Marek Vasut <marek.vasut@gmail.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

arch/mips/pnx833x/common/platform.c

@@ -266,6 +266,7 @@ pnx833x_flash_nand_cmd_ctrl(struct mtd_info *mtd, int cmd, unsigned int ctrl)
 
 static struct platform_nand_data pnx833x_flash_nand_data = {
 	.chip = {
+		.nr_chips		= 1,
 		.chip_delay		= 25,
 		.part_probe_types 	= part_probes,
 	},