nand, gpmc: fix reading after switching ecc

The omap_gpmc allows switching ecc at runtime. Since
the NAND_SUBPAGE_READ flag is only set, it is kept when
switching to hw ecc, which is not correct. This leads to
calling chip->ecc.read_subpage which is not a valid
pointer. Therefore clear the flag when switching ecc so
reading in hw mode works again.

Cc: Scott Wood <scottwood@freescale.com>
Cc: Pekon Gupta <pekon@ti.com>
Cc: Nikita Kiryanov <nikita@compulab.co.il>
Signed-off-by: Jeroen Hofstee <jeroen@myspectrum.nl>

drivers/mtd/nand/omap_gpmc.c

@@ -933,6 +933,7 @@ int __maybe_unused omap_nand_switch_ecc(uint32_t hardware, uint32_t eccstrength)
 	mtd = &nand_info[nand_curr_device];
 	nand = mtd->priv;
 	nand->options |= NAND_OWN_BUFFERS;
+	nand->options &= ~NAND_SUBPAGE_READ;
 	/* Setup the ecc configurations again */
 	if (hardware) {
 		if (eccstrength == 1) {