mpc8308_p1m: support for MPC8308 P1M board

This patch provides support for MPC8308 P1M board with the following
set of features:
 Dual UART is supported
 NOR flash is supported
 Both TSEC Ethernet controllers are supported
 PCI Express initialization is supported
 Both I2C controllers are supported

Signed-off-by: Ilya Yanok <yanok@emcraft.com>
Signed-off-by: Kim Phillips <kim.phillips@freescale.com>