atiixp/jmicron/triflex: fix PIO fallback

atiixp/jmicron/triflex: fix PIO fallback

* atiixp: if DMA can't be used atiixp_config_drive_for_dma() should return 0,
  atiixp_dma_check() will tune the correct PIO mode anyway

* jmicron: if DMA can't be used config_chipset_for_dma() should return 0,
  micron_config_drive_for_dma() will tune the correct PIO mode anyway

  config_jmicron_chipset_for_pio(drive, !speed) doesn't program
  device transfer mode for speed != 0 (only wastes some CPU cycles
  on ide_get_best_pio_mode() call) so remove it

* triflex: if DMA can't be used triflex_config_drive_for_dma() should return 0,
  triflex_config_drive_xfer_rate() will tune correct PIO mode anyway

Above changes also fix (theoretical) issue when ->speedproc fails to set
device transfer mode (i.e. when ide_config_drive_speed() fails to program it)
but one of DMA transfer modes is already enabled on the device by the BIOS.
In such scenario ide_dma_enable() will incorrectly return true statement
and ->ide_dma_check will try to enable DMA on the device.

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>