sparc32,sun4d: irq, smp files cleanup

- drop filename in file header
- drop unused includes
- add description of sun4d interrupts (from davem)
- add KERN_* to printk
- fix spaces => tabs
- add spaces after reserved words
- fix indent of a whole code block in smp4d_boot_one_cpu()
  Note: two printk() was updated from debug to KERN_INFO in this code block
- drop all externs, they are now in header files

This is partly based on a patch from: David Miller <davem@davemloft.net>

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: David S. Miller <davem@davemloft.net>