sparc64: unify arch/sparc64/oprofile/

A simple:

   diff arch/sparc64/oprofile/init.c arch/sparc/oprofile/init.c
   diff arch/sparc64/oprofile/Makefile arch/sparc/oprofile/Makefile

revealed that the directories were equal.
So let sparc64 point to the sparc version and drop the sparc64 oprofile dir

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