move alpha specific code into arch/alpha

move alpha specific code into arch/alpha
System -> AlphaSystem

SConscript:
    Move some more files around
arch/alpha/freebsd/system.cc:
arch/alpha/freebsd/system.hh:
    System -> AlphaSystem
arch/alpha/linux/aligned.hh:
arch/alpha/linux/hwrpb.hh:
arch/alpha/linux/system.cc:
arch/alpha/linux/thread_info.hh:
arch/alpha/linux/threadinfo.hh:
    move alpha specific code into arch/alpha
python/m5/objects/System.py:
    Split off arch specific parts of system into AlphaSystem

--HG--
rename : kern/freebsd/freebsd_system.cc => arch/alpha/freebsd/system.cc
rename : kern/freebsd/freebsd_system.hh => arch/alpha/freebsd/system.hh
rename : kern/linux/aligned.hh => arch/alpha/linux/aligned.hh
rename : kern/linux/hwrpb.hh => arch/alpha/linux/hwrpb.hh
rename : kern/linux/linux_system.cc => arch/alpha/linux/system.cc
rename : kern/linux/linux_system.hh => arch/alpha/linux/system.hh
rename : kern/linux/thread_info.hh => arch/alpha/linux/thread_info.hh
rename : kern/linux/linux_threadinfo.hh => arch/alpha/linux/threadinfo.hh
rename : kern/tru64/tru64_system.cc => arch/alpha/tru64/system.cc
rename : kern/tru64/tru64_system.hh => arch/alpha/tru64/system.hh
extra : convert_revision : 1c496efb823326a4b629574bd9b5f30e99a0aa40