some warnings fixes


include/m_ctype.h:
  New charset conversion fields in CHARSET_INFO
mysys/hash.c:
  Fix for "unused argument" warning
strings/ctype-big5.c:
  Fix for "unused argument" warning
strings/ctype-czech.c:
  Fix for "unused argument" warning
strings/ctype-euc_kr.c:
  Fix for "unused argument" warning
strings/ctype-gb2312.c:
  Fix for "unused argument" warning
strings/ctype-gbk.c:
  Fix for "unused argument" warning
strings/ctype-latin1_de.c:
  Fix for "unused argument" warning
strings/ctype-simple.c:
  8bit<->unicode convertion routines
strings/ctype-sjis.c:
  Fix for "unused argument" warning
strings/ctype-tis620.c:
  Fix for "unused argument" warning
strings/ctype-ujis.c:
  Fix for "unused argument" warning
strings/ctype-utf8.c:
  Fix for "unused argument" warning
strings/ctype.c:
  8bit <-> unicode conversion tables