m68k/atari - ataflop: use correct virt/phys translation for DMA buffer

With the kernel running from FastRAM instead of ST-RAM, none of ST-RAM is
mapped by mem_init, and DMA-addressable buffer must be mapped by ioremap.

Use platform specific virt/phys translation helpers for this case.
Signed-off-by: Michael Schmitz <schmitz@debian.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>

drivers/block/ataflop.c

@@ -1952,7 +1952,7 @@ static int __init atari_floppy_init (void)
 		goto Enomem;
 	}
 	TrackBuffer = DMABuffer + 512;
-	PhysDMABuffer = virt_to_phys(DMABuffer);
+	PhysDMABuffer = atari_stram_to_phys(DMABuffer);
 	PhysTrackBuffer = virt_to_phys(TrackBuffer);
 	BufferDrive = BufferSide = BufferTrack = -1;