split uart into urt8250 and uart8530

split uart into urt8250 and uart8530
fix some doxygen comments

SConscript:
    Added split uart files
dev/ns_gige.cc:
dev/ns_gige.hh:
dev/ns_gige_reg.h:
dev/tsunami.cc:
dev/tsunami_cchip.cc:
dev/tsunami_io.cc:
dev/tsunami_pchip.cc:
dev/tsunamireg.h:
    fix doxgyen file comment
dev/uart.cc:
dev/uart.hh:
python/m5/objects/Uart.py:
    split uart into urt8250 and uart8530

--HG--
extra : convert_revision : 2e70aad892a37620d7909017648bca6d7d69d678