powerpc/fsl-booke: Add T1024 RDB board support

T1024RDB is a Freescale Reference Design Board that hosts the T1024 SoC.

Signed-off-by: Shengzhou Liu <Shengzhou.Liu@freescale.com>
[scottwood:  vendor prefix: s/at24/atmel/ and trimmed detailed
 board description with too-long lines]
Signed-off-by: Scott Wood <scottwood@freescale.com>