* m68k: Fixed parameter passing to conform to ABI:
  * records are passed by value
  * records with size of 1,2 or 4 are returned in registers
  * parameters with size<4 are justified on the stack according to big-endian target

Now everything except floating-point parameters is compatible with C code compiled with "-malign-int -mrtd".
Compatibility with "-mno-align-int" is achievable by changing target_info.maxCrecordalign to 2, but doings so causes a lot more troubles because RTL (incorrectly) assumes that records declared with {$PACKRECORDS C} are aligned to pointer size.

+ Reuse parameter locations. Since everything is passed on stack, it reduces code size quite a bit.
- tm68kparamanager.getintparaloc removed, generic implementation has been tested and works as expected.

git-svn-id: http://svn.freepascal.org/svn/fpc/trunk@28083 3ad0048d-3df7-0310-abae-a5850022a9f2