[PATCH] Remove unnecessary kmalloc/kfree calls in mtdchar

This patch removes repeated calls to kmalloc / kfree in mtd_write /
mtd_read functions, replacing them by a single kmalloc / kfree pair.

Signed-off-by: Thiago Galesi <thiagogalesi@gmail.com>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>