re PR target/17306 (function_vector attribute in H8300H/H8S)

re PR target/17306 (function_vector attribute in H8300H/H8S)

	PR target/17306
	* config/h8300/constraints.md (U): Correctly dectect
	"eightbit_data" memory addresses.
	* config/h8300/h8300.c (eightbit_constant_address_p): Also
	handle (const (plus (symbol_ref (x)))) where x is declared
	as an 8-bit data memory address.
	* config/h8300/h8300.md (call, call_value): Correctly detect
	"funcvec" functions.

	PR target/17306
	* gcc.target/h8300/pr17306-1.c: New test.
	* gcc.target/h8300/pr17306-2.c: New test.

From-SVN: r220472