sgiioc4: fix messages

sgiioc4: fix messages

Fix several issues with the log messages printed by ide_dma_sgiioc4() and
sgiioc4_ide_setup_pci_device():

- IOC4 registers are memory-mapped but the "BM-DMA at" format corresponds to
  I/O  mapped registers;

- "%p" format specifiers and type casts used to print non-pointer values;

- using KERN_INFO log level for the error message;

- 'hwif->name' printed as drive's name.

While at it, also:

- return more fitting -EBUSY if request_mem_region() fails;

- make the error message style consistent;

- fix indentation, put the printk() facility and message on the same line;

- use comparisions with NULL instead of ! operator..

Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Cc: jeremy@sgi.com
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>