unwind-dw2-fde.h (last_fde): Use "(const fde *)" instead of "(char *)" to avoid qualifier warning by 'xgcc'...

 	* unwind-dw2-fde.h (last_fde): Use "(const fde *)" instead of
 	"(char *)" to avoid qualifier warning by 'xgcc' compiling.

From-SVN: r220004