ppc4xx: ML507 Board Support

The Xilinx ML507 Board is a Virtex 5 prototyping board that includes,
	among others:
	-Virtex 5 FX FPGA (With a ppc440x5 in it)
	-256MB of SDRAM2
	-32MB of Flash
	-I2C Eeprom
	-System ACE chip
	-Serial ATA connectors
	-RS232 Level Conversors
	-Ethernet Transceiver

This patch gives support to a standard design produced by EDK for this
board: ppc440, uartlite, xilinx_int and flash

- Includes Changes propossed by Stefan Roese and Michal Simek

Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@uam.es>
Acked-by: Stefan Roese <sr@denx.de>