Bluetooth: RFCOMM: Respond to RLS command

If remote sends RLS command then it should be responded with the
value received.

> ACL Data RX: Handle 256 flags 0x02 dlen 12
      Channel: 64 len 8 [PSM 3 mode 0] {chan 0}
      RFCOMM: Unnumbered Info with Header Check (UIH) (0xef)
         Address: 0x03 cr 1 dlci 0x00
         Control: 0xef poll/final 0
         Length: 4
         FCS: 0x70
         MCC Message type: Remote Line Status CMD (0x14)
           Length: 2
           dlci 10 error: 5

< ACL Data TX: Handle 256 flags 0x00 dlen 12
      Channel: 64 len 8 [PSM 3 mode 0] {chan 0}
      RFCOMM: Unnumbered Info with Header Check (UIH) (0xef)
         Address: 0x01 cr 0 dlci 0x00
         Control: 0xef poll/final 0
         Length: 4
         FCS: 0xaa
         MCC Message type: Remote Line Status RSP (0x14)
           Length: 2
           dlci 10 error: 5

Change-Id: Ib70e02aede2088bca748d1eb68bee9b1bc47a65d
Signed-off-by: Jaganath Kanakkassery <jaganathx.kanakkassery@intel.com>