* ST AMBA bus config

- bridge_type2 : Bridge type new generation.
		 else
		 Bridge type older version.

Type of transaction to generate on stbus side
- max_opcode_LD4_ST4
- max_opcode_LD8_ST8
- max_opcode_LD16_ST16
- max_opcode_LD32_ST32
- max_opcode_LD64_ST64

- chunks_in_msg : Integer value, defines the maximum number of chunk an STBus
  message may be built of at any time.
- packets_in_chunk : Integer value, defines the maximum number of chunk an STBus
  message may be built of at any time.

- write_posting	: To enable write-posting.

Fields unique to v1
- req_timeout

Fields unique to v2
- sd_config_missing : Some of the bridges do not have sd_config register.

- threshold : Integer value specifies the minimum number of data bytes to be stored
  at consecutive addresses which must be available in the
  Request FIFO in order to start issuing an STBus burst.

- req_notify_cell_based	: Specifies when an AHB transaction is to be started.
  Cell based transaction is started as soon as one STBus cell is received.
  If this property is not specified it selects "burst-based".
  When burst based is selected, transaction is started as soon as an
  AHB burst is ready in the Request FIFOs.

- complete_on_error : Specifies what the behaviour the bridge has to be when an
  error response is encountered on the AHB side.
  The current transaction is carried on to its completion if property specified,
  else the current transaction is aborted.

- merge_msg : Message merge feature enable/disable.

- cell_based_trigger : Specifies whether the generation of STBus transactions
  has to be cell-based.if the property is not specified,
  the trigger defaults to be threshold-based.

- read_ahead : Read ahead feature enable/disable.

- set_by_boot : Config is set directly by boot stage. If set, bridge_type2
		field is mandatory and sd_config_missing is optional. Other
		fields are not available.

Example:

	ethernet-bus-config: st-eth-amba-bridge {
		reg-offset = <0x1FFC>;
		bridge_type2;
		chunks_in_msg = <1>;
		packets_in_chunk = <2>;
		write_posting;
		max_opcode_LD64_ST64;
		threshold = <512>;
		sd_config_missing;
		read_ahead;
	};
