Improve the cpu type handling for M68k just in case we should branch 2.8.0 before I can start working on M68k again.
Therefor the cpu type (-Cp...) "coldfire" was split up into "isaa", "isaa+", "isab" and "isac". The Linux RTL can currently compiled for "68020", "isab" and "isac". For the other three Bcc.L must be handled differently (only Bcc.B/W supported) and for "68000" also EXT.L needs to be handled differently.

fpcdefs.inc:
  + define CPUCAPABILITIES if capabilities can be set for a certain CPU type (currently ARM, AVR and M68k)
options.pas:
  * check for CPUCAPABILITIES instead of specific CPUs
assemble.pas:
  - the handling of the CPU type is already done in m68k/ag68kgas.pas, Tm68kGNUAssembler.MakeCmdLine (and thereby already using the gascputypestr array!)
m68k/cpuinfo.pas:
  - tcputype: remove "cpu_coldfire"
  + tcputype: add "cpu_isa_a", "cpu_isa_a_p", "cpu_isa_b" and "cpu_isa_c"
  + add "cpu_coldfire" constant which contains all Coldfire specific cpu types
  * adjust "cputypestr" and  "gascputypestr"
  + add tcpuflags and cpu_capabilities (DBRA restriction was checked with CPUCOLDFIRE, CAS/TAS will be needed for atomic operations and BRAL restriction was discovered during testing of new cpu types)
m68k/cgcpu.pas:
  * adjust checks for "cpu_coldfire"
m68k/n68kadd.pas:
  * don't use a BRA.L if it is not supported, but (at least for now) a BRA.W
aggas.pas:
  * adjusted check for Coldfire


git-svn-id: http://svn.freepascal.org/svn/fpc/trunk@25457 3ad0048d-3df7-0310-abae-a5850022a9f2