Fix Sparc64 boot on i386 host:

Fix Sparc64 boot on i386 host:
 - move do_interrupt() back to op_helper.c
 - move non-helper prototypes from helper.h to exec.h
 - move some prototypes from cpu.h to exec.h
 - do not export either set_cwp() or cpu_set_cwp() from op_helper.c,
   but instead provide inline functions

git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5109 c046a42c-6fe2-441c-8c8c-71466251a162