so replace a branch with a 'sir'
- in #if 0 code, in sparc64_ipi_flush_pte() and sparc64_ipi_flush_ctx()
save/restore the out registers that the sp_tlb_flush_xxx() versions
around calling them
- in sp_tlb_flush_pte() and sp_tlb_flush_ctx(), replace global register
usage with out registers so that we don't clobber the (alternate)
global registers when these are called from IPI context