[source] ar71xx: fix rb922gs_nand_scan_fixup()

[LEDE Commits]

mkresin pushed a commit to source.git, branch master:
https://git.lede-project.org/8927446dae819c45cee178629dca612c90edd886

commit 8927446dae819c45cee178629dca612c90edd886
Author: Roger Pueyo Centelles <roger.pueyo at guifi.net>
AuthorDate: Thu Dec 21 15:51:10 2017 +0100

    ar71xx: fix rb922gs_nand_scan_fixup()
    
    Apply code from commits 9e1bc27e6d67fa29791eb0fac5e5f0066d12a761
    (ar71xx: Fix UBIFS work on Mikrotik RB95x devices) and
    665bb2749906aff4d4ec607a308353fa30cb1b3a (ar71xx: fix invalid pointer
    dereference in rb95x_nand_scan_fixup()) to RB92x devices too.
    
    Signed-off-by: Roger Pueyo Centelles <roger.pueyo at guifi.net>
---
 target/linux/ar71xx/files/arch/mips/ath79/mach-rb922.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/target/linux/ar71xx/files/arch/mips/ath79/mach-rb922.c b/target/linux/ar71xx/files/arch/mips/ath79/mach-rb922.c
index 577fb0e..223b505 100644
--- a/target/linux/ar71xx/files/arch/mips/ath79/mach-rb922.c
+++ b/target/linux/ar71xx/files/arch/mips/ath79/mach-rb922.c
@@ -195,7 +195,9 @@ static int rb922gs_nand_scan_fixup(struct mtd_info *mtd)
 {
 #if LINUX_VERSION_CODE < KERNEL_VERSION(4,6,0)
 	struct nand_chip *chip = mtd->priv;
-#endif
+#else
+	struct nand_chip *chip = mtd_to_nand(mtd);
+#endif /* < 4.6.0 */
 
 	if (mtd->writesize == 512) {
 		/*
@@ -209,6 +211,8 @@ static int rb922gs_nand_scan_fixup(struct mtd_info *mtd)
 #endif
 	}
 
+	chip->options = NAND_NO_SUBPAGE_WRITE;
+
 	return 0;
 }