* write.c (TC_FORCE_RELOCATION_SUB_LOCAL): Heed md_register_arithmetic.
(TC_VALIDATE_FIX_SUB): Likewise.
* config/tc-frv.h (TC_FORCE_RELOCATION_SUB_LOCAL): Likewise.
* config/tc-hppa.h (TC_FORCE_RELOCATION_SUB_LOCAL): Likewise.
* config/tc-mn10300.h (TC_VALIDATE_FIX_SUB): Likewise.
* config/tc-sh.h (TC_VALIDATE_FIX_SUB): Likewise.
(TC_FORCE_RELOCATION_SUB_LOCAL): Likewise.
* config/tc-sh64.h (TC_VALIDATE_FIX_SUB): Likewise.
* config/tc-xtensa.h (TC_VALIDATE_FIX_SUB): Likewise.
* doc/internals.texi (TC_FORCE_RELOCATION_SUB_ABS,
TC_FORCE_RELOCATION_SUB_LOCAL, TC_VALIDATE_FIX_SUB): Show new param.