Enable the isdram command on the MPC8360EMDS board

The isdram command prints out decoded information the "serial presence
detect" (SPD) chip on the SDRAM SIMMs.  This can be very helpful when
debugging memory configuration problems.

Signed-off-by: Gerald Van Baren <vanbaren@cideas.com>
Signed-off-by: Kim Phillips <kim.phillips@freescale.com>