toshiba: use ioremap_cached

The switch of ioremap to default to uncached doesn't break this driver
but it does needlessly slow it down as BIOS space is cachable and this
driver is quite happy scanning cached ROM space.

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>