add ISA_HAS_DELAY_SLOT directive instead of "#if THE_ISA == ALPHA_ISA" throughout...

add ISA_HAS_DELAY_SLOT directive instead of "#if THE_ISA == ALPHA_ISA" throughout CPU models

src/arch/alpha/isa_traits.hh:
src/arch/mips/isa_traits.hh:
src/arch/sparc/isa_traits.hh:
    define 'ISA_HAS_DELAY_SLOT'
src/cpu/base_dyn_inst.hh:
src/cpu/o3/bpred_unit_impl.hh:
src/cpu/o3/commit_impl.hh:
src/cpu/o3/cpu.cc:
src/cpu/o3/cpu.hh:
src/cpu/o3/decode_impl.hh:
src/cpu/o3/fetch_impl.hh:
src/cpu/o3/iew_impl.hh:
src/cpu/o3/inst_queue_impl.hh:
src/cpu/o3/rename_impl.hh:
src/cpu/simple/base.cc:
    use ISA_HAS_DELAY_SLOT instead of THE_ISA == ALPHA_ISA

--HG--
extra : convert_revision : 24c7460d9391e8d443c9fe08e17c331ae8e9c36a