TDBF: fixed some unaligned memory accesses causing SIGBUS on ARM

git-svn-id: http://svn.freepascal.org/svn/fpc/trunk@24155 3ad0048d-3df7-0310-abae-a5850022a9f2
fcl-db/dbase:
* attempt fix for mantis #10174: don't pass DBase size for ftBCD fields
  when creating FPC fields. to do: verify if we need to do this for other
	field types (ftWideString?)
* cosmetic clarifications

git-svn-id: http://svn.freepascal.org/svn/fpc/trunk@24156 3ad0048d-3df7-0310-abae-a5850022a9f2