sis5513: remove /proc/ide/sis

This belongs to user-space (and only if really needed).

   text    data     bss     dec     hex filename
   7129     404       8    7541    1d75 drivers/ide/pci/sis5513.o.before
   3916     404       1    4321    10e1 drivers/ide/pci/sis5513.o.after

Additionaly to being bloat the code contained two bugs:
- wrong cable bit was checked (0x0001 instead of 0x8000) on ATA_133 chipsets
- incorrect UDMA cycle time was reported on ATA_100a/ATA_133 chipsets

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