bluetooth: avdtp: implement the avdtp fragmentation and reassembly

Define BT_AVDTP_SIGNAL_SDU_MAX Kconfig item to limit the max avdtp signal
SDU size, then use avdtp self defined net buf pool to prepare data. Use
default acl_tx_pool pool do to the fragmentation.

Signed-off-by: Mark Wang <[email protected]>

Author: MarkWangChinese

subsys/bluetooth/host/classic/Kconfig

@@ -444,6 +444,14 @@ config BT_AVDTP_RTP_VERSION
 	help
 	  This option sets the AVDTP RTP protocol version
 
+config BT_AVDTP_SIGNAL_SDU_MAX
+	int "Maximum size of AVDTP signaling SDU"
+	default 512
+	range 48 $(UINT16_MAX)
+	help
+	  This option sets the maximum size of AVDTP signaling SDU.
+	  The default value is 512 bytes.
+
 endif # BT_AVDTP
 
 if BT_A2DP