libsframe: replace an strncat with strcat

libsframe: replace an strncat with strcat

Calling strncat with the size of the src string is not so meaningful.
The length argument to strncat should specify the remaining bytes
bytes in the destination; although in this case, it appears to be
unncessary altogether to use strncat in the first place.

libsframe/
        * sframe-dump.c (dump_sframe_func_with_fres): Use of strcat is
	just as fine.