This commit add initial support for Freescale (NXP) P2020RDB

Hardware:
SoC: P2020 2x1GHz
DRAM: 512-1GB DDR3
2 + 4 GBE (2 separate ports and four in VSC7385)
Flash: 16MB NOR, 32MB NAND, 16MB SPI-NOR
PCIE x1 and mPCIE x1
SD Reader

Interfaces:
GBE RJ45 x6
USB2.0 x1
UART x2
I2C x2
JTAG x1
SD x1
PCIE x2 (PCIE and mPCIE)

Flash instructions:
Place sysupgrade image to 0x80000 address in NOR.
Eg. (no brakelines in setenv command):

setenv 'firmware_flash tftpboot $loadaddr $firmwarefile;
 protect off $norfdtaddr +$filesize; erase $norfdtaddr +$filesize;
 cp.b $loadaddr $norfdtaddr $filesize; protect on $norfdtaddr +$filesize;
 cmp.b $loadaddr $norfdtaddr $filesize'
setenv firmwarefile firmware.bin
run firmware_flash

Boot (no brakeline in setenv command):
setenv bootcmd 'setenv bootargs root=/dev/mtdblock3 rw console=$consoledev,
$baudrate rootfstype=squashfs $othbootargs;
bootm $norfdtaddr'
saveenv
boot

Known issues:
-Switch is unmanaged (VSC 7385 is connected via eLBC, driver uses SPI)
-No SD reader support

Signed-off-by: Pawel Dembicki <paweldembicki@gmail.com>
Signed-off-by: Christian Lamparter <chunkeey@gmail.com> [refreshed patches]