mtd: make pagetest work

The mtd_pagetest test did not initialize the pgsize variable, which
basically means it did not work. This problem was reported by
Török Edwin <edwintorok@gmail.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

drivers/mtd/tests/mtd_pagetest.c

@@ -523,6 +523,7 @@ static int __init mtd_pagetest_init(void)
 	do_div(tmp, mtd->erasesize);
 	ebcnt = tmp;
 	pgcnt = mtd->erasesize / mtd->writesize;
+	pgsize = mtd->writesize;
 
 	printk(PRINT_PREF "MTD device size %llu, eraseblock size %u, "
 	       "page size %u, count of eraseblocks %u, pages per "