sparc32,sun4m: irq, smp files cleanup

- drop filename in file header
- drop unused includes
- add description of sun4m interrupts (from davem)
- add KERN_* to printk
- fix spaces => tabs
- add spaces after reserved words
- 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>