alim15x3: disable init_hwif_ali15x3 for PowerPC

We don't need init_hwif_ali15x3() on the PowerPC systems either.

Before:

ALI15X3: IDE controller (0x10b9:0x5229 rev 0xc8) at  PCI slot 0001:03:1f.0
ALI15X3: 100% native mode on irq 19
    ide0: BM-DMA at 0x1120-0x1127
    ide1: BM-DMA at 0x1128-0x112f
hda: SONY DVD RW AW-Q170A, ATAPI CD/DVD-ROM drive
hda: UDMA/66 mode selected
ide0: Disabled unable to get IRQ 14.
ide0: failed to initialize IDE interface
ide1: Disabled unable to get IRQ 15.
ide1: failed to initialize IDE interface

After:

ALI15X3: IDE controller (0x10b9:0x5229 rev 0xc8) at  PCI slot 0001:03:1f.0
ALI15X3: 100% native mode on irq 19
    ide0: BM-DMA at 0x1120-0x1127
    ide1: BM-DMA at 0x1128-0x112f
hda: SONY DVD RW AW-Q170A, ATAPI CD/DVD-ROM drive
hda: UDMA/66 mode selected
ide0 at 0x1100-0x1107,0x110a on irq 19
ide1 at 0x1110-0x1117,0x111a on irq 19
hda: ATAPI 48X DVD-ROM DVD-R CD-R/RW drive, 2048kB Cache

ide0 works well, though I can't test ide1, it isn't traced out on
the board.

Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>