sparc32: remove sun4c traps

We used to runtime patch the trap table for srmmu.
With the removal of sun4c support this is no longer required.

With the sun4c trap removed we can remove all the referenced
trap handling which is sun4c specific.
This also allows us to get rid of the nosun4c.c file that
contained only dummy functions/data.

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