Rename ms1 files to mt files (part 1 -- renames only)

bfd/cpu-mt.c

bfd/elf32-mt.c

cpu/mt.cpu

cpu/mt.opc

gas/config/tc-mt.c

gas/config/tc-mt.h

gas/doc/c-mt.texi

gas/testsuite/gas/mt/allinsn.d

gas/testsuite/gas/mt/allinsn.s

gas/testsuite/gas/mt/badinsn.s

gas/testsuite/gas/mt/badinsn1.s

gas/testsuite/gas/mt/badoffsethigh.s

gas/testsuite/gas/mt/badoffsetlow.s

gas/testsuite/gas/mt/badorder.s

gas/testsuite/gas/mt/badreg.s

gas/testsuite/gas/mt/badsignedimmhigh.s

gas/testsuite/gas/mt/badsignedimmlow.s

gas/testsuite/gas/mt/badsyntax.s

gas/testsuite/gas/mt/badsyntax1.s

gas/testsuite/gas/mt/badunsignedimmhigh.s