Bluetooth: RFCOMM: Disconnect session after last dlc disconnection
Bluetooth: RFCOMM: Disconnect session after last dlc disconnection

As per the spec the station which disconnects last dlc should initiate
session disconnection and then l2cap disconnection.

< ACL Data TX: Handle 256 flags 0x00 dlen 8
      Channel: 64 len 4 [PSM 3 mode 0] {chan 0}
      RFCOMM: Disconnect (DISC) (0x43)
         Address: 0x03 cr 1 dlci 0x00
         Control: 0x53 poll/final 1
         Length: 0
         FCS: 0xfd

> ACL Data RX: Handle 256 flags 0x02 dlen 8
      Channel: 64 len 4 [PSM 3 mode 0] {chan 0}
      RFCOMM: Unnumbered Ack (UA) (0x63)
         Address: 0x01 cr 0 dlci 0x00
         Control: 0x73 poll/final 1
         Length: 0
         FCS: 0xb6

Change-Id: I2d1d7d284995529d5d1522e0ca6082097db19bc2
Signed-off-by: Jaganath Kanakkassery <cdeedb43633a09d3dc68b67af94002f918d6c778@intel.com>

tidyjiang8/zephyr-doc,zephyrproject-rtos/zephyr,tidyjiang8/zephyr-doc,nashif/zephyr,zephyrproject-rtos/zephyr,kraj/zephyr,rsalveti/zephyr,erwango/zephyr,mbolivar/zephyr,holtmann/zephyr,zephyriot/zephyr,bigdinotech/zephyr,GiulianoFranchetto/zephyr,punitvara/zephyr,aceofall/zephyr-iotos,explora26/zephyr,fractalclone/zephyr-riscv,aceofall/zephyr-iotos,runchip/zephyr-cc3200,punitvara/zephyr,galak/zephyr,galak/zephyr,sharronliu/zephyr,holtmann/zephyr,mbolivar/zephyr,ldts/zephyr,bigdinotech/zephyr,sharronliu/zephyr,bboozzoo/zephyr,zephyrproject-rtos/zephyr,mbolivar/zephyr,zephyriot/zephyr,Vudentz/zephyr,pklazy/zephyr,nashif/zephyr,tidyjiang8/zephyr-doc,bigdinotech/zephyr,fbsder/zephyr,bigdinotech/zephyr,runchip/zephyr-cc3220,runchip/zephyr-cc3200,bboozzoo/zephyr,fbsder/zephyr,pklazy/zephyr,runchip/zephyr-cc3220,fbsder/zephyr,Vudentz/zephyr,pklazy/zephyr,holtmann/zephyr,erwango/zephyr,explora26/zephyr,explora26/zephyr,bboozzoo/zephyr,erwango/zephyr,GiulianoFranchetto/zephyr,fractalclone/zephyr-riscv,pklazy/zephyr,fractalclone/zephyr-riscv,erwango/zephyr,kraj/zephyr,finikorg/zephyr,sharronliu/zephyr,nashif/zephyr,punitvara/zephyr,runchip/zephyr-cc3220,zephyriot/zephyr,explora26/zephyr,runchip/zephyr-cc3220,aceofall/zephyr-iotos,galak/zephyr,fbsder/zephyr,ldts/zephyr,punitvara/zephyr,zephyriot/zephyr,bboozzoo/zephyr,aceofall/zephyr-iotos,rsalveti/zephyr,Vudentz/zephyr,kraj/zephyr,rsalveti/zephyr,rsalveti/zephyr,Vudentz/zephyr,zephyrproject-rtos/zephyr,punitvara/zephyr,ldts/zephyr,tidyjiang8/zephyr-doc,kraj/zephyr,holtmann/zephyr,explora26/zephyr,tidyjiang8/zephyr-doc,sharronliu/zephyr,finikorg/zephyr,zephyriot/zephyr,aceofall/zephyr-iotos,sharronliu/zephyr,fbsder/zephyr,ldts/zephyr,nashif/zephyr,fractalclone/zephyr-riscv,mbolivar/zephyr,bboozzoo/zephyr,runchip/zephyr-cc3200,Vudentz/zephyr,GiulianoFranchetto/zephyr,runchip/zephyr-cc3220,finikorg/zephyr,holtmann/zephyr,zephyrproject-rtos/zephyr,GiulianoFranchetto/zephyr,fractalclone/zephyr-riscv,finikorg/zephyr,rsalveti/zephyr,pklazy/zephyr,mbolivar/zephyr,ldts/zephyr,runchip/zephyr-cc3200,galak/zephyr,erwango/zephyr,runchip/zephyr-cc3200,bigdinotech/zephyr,Vudentz/zephyr,finikorg/zephyr,kraj/zephyr,GiulianoFranchetto/zephyr,nashif/zephyr,galak/zephyr