make ldtw(a) -- Twin 32 bit load work correctly -- by doing it the same way as the...

make ldtw(a) -- Twin 32 bit load work correctly -- by doing it the same way as the twin 64 bit loads

src/arch/isa_parser.py:
src/arch/sparc/isa/decoder.isa:
src/arch/sparc/isa/operands.isa:
src/base/bigint.hh:
src/cpu/simple/atomic.cc:
src/cpu/simple/timing.cc:
src/mem/packet_access.hh:
    make ldtw(a) Twin 32 bit load work correctly

--HG--
extra : convert_revision : 2646b269d58cc1774e896065875a56cf5e313b42