[MIPS] Pb1200/DBAu1200: move platform code to its proper place

Since both the IDE interface and SMC 91C111 Ethernet chip are on-board
devices, not SOC devices, move the platform device registration form the
common to the board specific code.

While at it, remove semicolon (which didn't break compilation only by
chance) from the AU1XXX_ATA_DDMA_REQ macro and do some renaming:

- change 'au1200_ide0_' variable name prefix to the mere 'ide_';

- change 'smc91x_' variable name prefix to 'smc91c111_' since that's the
  name of the chip used on the boards;

- drop 'AU1XXX_' prefix from the names of macros describing IDE and Ethernet
  on-board devices;

- change 'SMC91111_' to 'SMC91C111_', change 'IRQ' to 'INT' in the names of
  the macros describing the Ethernet chip for consistency with the IDE
  macros;

- change 'ATA_' to 'IDE_' and 'OFFSET' to 'SHIFT' (since this value is
  indeed a shift count) in the names of the macros describing the IDE
  interface.

Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>