cris: sprintf sanitizer null destination pointer

cris: sprintf sanitizer null destination pointer

Simplify the sprintf calls, and use sprintf return value.  Older code
in binutils avoided using the sprintf return count of chars printed,
because with some older C libraries it wasn't reliable.  Nowadays it
should be OK to use (and we already use the return value elsewhere).
sprintf can't return an error status of -1 here.

	* cris-dis.c (format_dec): Avoid sanitizer warning.  Use sprintf
	return value rather than calling strlen.