Remove duplicated charset definitions, and move them to fx_font.h

PWL_FontMap does not need its own charset definitions. fx_edit.h does
not need to define DEFAULT_CHARSET. XFA have their own definitions.
They look different in that most are MAC or MSWin charset definitions.
So they are left untouched. public/fpdf_sysfontinfo.h duplicate ones
were left untouched due to being in public folder.

Review-Url: https://codereview.chromium.org/2347313002
diff --git a/fpdfsdk/cfx_systemhandler.cpp b/fpdfsdk/cfx_systemhandler.cpp
index 08d9743..cbd929f 100644
--- a/fpdfsdk/cfx_systemhandler.cpp
+++ b/fpdfsdk/cfx_systemhandler.cpp
@@ -26,7 +26,7 @@
     return 932;
   if (charset == FXFONT_GB2312_CHARSET)
     return 936;
-  if (charset == FXFONT_HANGEUL_CHARSET)
+  if (charset == FXFONT_HANGUL_CHARSET)
     return 949;
   if (charset == FXFONT_CHINESEBIG5_CHARSET)
     return 950;