monitor: Add option to suppress HCI vendor events

When idle, Marvell 88W8897 Bluetooth adapter sends the following
HCI vendor events to BlueZ stack on continuous basis:

$ btmon
Bluetooth monitor ver 5.43
= New Index: XX:XX:XX:XX:XX:XX (Primary,SDIO,hci0)   [hci0] 0.029199
= Open Index: XX:XX:XX:XX:XX:XX                      [hci0] 0.029211
= Index Info: XX:XX:XX:XX:XX:XX (Marvell Technology Group Ltd.)
                                                     [hci0] 0.029222
> HCI Event: Vendor (0xff) plen 5                    [hci0] 0.300944
        05 80 00 09 00
> HCI Event: Vendor (0xff) plen 5                    [hci0] 2.860113
        05 80 00 09 00
> HCI Event: Vendor (0xff) plen 5                    [hci0] 5.420643
        05 80 00 09 00
  ...

Add option to suppress these HCI vendor events from btmon log.

Change-Id: I357ef2c65c3ea18faf6a4462c7e70d2fc92219db
3 files changed