ppc4xx: add support for new PMC440 revision with cleanup

This patch adds support for the new PMC440 hardware revision 1.4.
The board now uses Micrel KSZ9031 phys.

Add missing i2c initialization before reading bootstrap eeprom.

Fix a couple of coding style issues.

Make local functions static.

Signed-off-by: Matthias Fuchs <matthias.fuchs@esd.eu>
Signed-off-by: Stefan Roese <sr@denx.de>