mtd: tests: fix read, speed and stress tests on NOR flash

Before using block_isbad() check if mtd->block_isbad() is defined.
Calculating pgcnt must be done using pgsize defined to 512 on
NOR and mtd->writesize for NAND, not using  mtd->writesize directly.

Signed-off-by: Morten Thunberg Svendsen <mts.doredevelopment@gmail.com>
Acked-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
diff --git a/drivers/mtd/tests/mtd_readtest.c b/drivers/mtd/tests/mtd_readtest.c
index 79fc453..25c5dd0 100644
--- a/drivers/mtd/tests/mtd_readtest.c
+++ b/drivers/mtd/tests/mtd_readtest.c
@@ -147,6 +147,10 @@
 	}
 	memset(bbt, 0 , ebcnt);
 
+	/* NOR flash does not implement block_isbad */
+	if (mtd->block_isbad == NULL)
+		return 0;
+
 	printk(PRINT_PREF "scanning for bad eraseblocks\n");
 	for (i = 0; i < ebcnt; ++i) {
 		bbt[i] = is_block_bad(i) ? 1 : 0;
@@ -184,7 +188,7 @@
 	tmp = mtd->size;
 	do_div(tmp, mtd->erasesize);
 	ebcnt = tmp;
-	pgcnt = mtd->erasesize / mtd->writesize;
+	pgcnt = mtd->erasesize / pgsize;
 
 	printk(PRINT_PREF "MTD device size %llu, eraseblock size %u, "
 	       "page size %u, count of eraseblocks %u, pages per "