[POWERPC] 85xx: Clean up from 85xx_ds rename

Renamed functions in 85xx_ds from 8544 to 85xx.

Kept an unique machine def/probe for the MPC8544 DS board to
handle some subtle differences between the future board based
on the DS platform.

Also fixed building w/o CONFIG_PCI and minor whitespace fixes.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>