mtd: nand: Declare tBERS, tR and tPROG as u64 to avoid integer overflow

All timings in nand_sdr_timings are expressed in picoseconds but some
of them may not fit in an u32.

Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Fixes: 204e7ecd47e2 ("mtd: nand: Add a few more timings to nand_sdr_timings")
Reported-by: Alexander Dahl <ada@thorsis.com>
Cc: <stable@vger.kernel.org>
Reviewed-by: Alexander Dahl <ada@thorsis.com>
Tested-by: Alexander Dahl <ada@thorsis.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
diff --git a/include/linux/mtd/nand.h b/include/linux/mtd/nand.h
index 892148c..5216d2e 100644
--- a/include/linux/mtd/nand.h
+++ b/include/linux/mtd/nand.h
@@ -681,10 +681,10 @@
  * @tWW_min: WP# transition to WE# low
  */
 struct nand_sdr_timings {
-	u32 tBERS_max;
+	u64 tBERS_max;
 	u32 tCCS_min;
-	u32 tPROG_max;
-	u32 tR_max;
+	u64 tPROG_max;
+	u64 tR_max;
 	u32 tALH_min;
 	u32 tADL_min;
 	u32 tALS_min;