mostly implemented SOFTINT relevant interrupt stuff.

mostly implemented SOFTINT relevant interrupt stuff.

src/arch/sparc/interrupts.hh:
    add in thread_context.hh to get access to tc.
    get rid of stubs that don't make sense right now.
    implement checking and get softint interrupts
src/arch/sparc/miscregfile.cc:
    softint should be OR-ed on a write.
src/arch/sparc/miscregfile.hh:
    add some enums for state fields for easy access to bitmasks of HPSTATE and PSTATE regs.
src/arch/sparc/ua2005.cc:
    implement writing SOFTINT, PSTATE, PIL, and HPSTATE properly, add helpful info to panic for bad reg write.

--HG--
extra : convert_revision : d12d1147b508121075ee9be4599693554d4b9eae