ARM: dts: omap3: Fix memory node in Torpedo board

Commit ("766a1fe7 ARM: omap3: Add missing memory node") added
the memory node, but the patch didn't have the correct starting address.

This patch fixes the correct starting address.

Signed-off-by: Adam Ford <aford173@gmail.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>