AlgSupported checks reserved bits

[steven-bellock]

For example

libspdm/library/spdm_responder_lib/libspdm_rsp_algorithms.c

Lines 457 to 462 in 5ebe5e3

	case SPDM_NEGOTIATE_ALGORITHMS_STRUCT_TABLE_ALG_TYPE_DHE:
	if (struct_table->alg_supported == 0) {
	return libspdm_generate_error_response(
	spdm_context, SPDM_ERROR_CODE_INVALID_REQUEST,
	0, response_size, response);
	}

where DHE only uses seven bits. A mask needs to be applied so that reserved bits are not checked.

[steven-bellock]

This looks like it's needed in lots of other algorithms. This issue will focus on the AlgType ones.

[steven-bellock]

I will make a pull request to just introduce helper functions that return masks based on the negotiated SPDM version.