Bluetooth: hci: added HCI vendor-specific Setup function feature

- Added config BT_HCI_SETUP to enable HCI vendor-specific Setup feature,
- Added pointer to 'setup' function in bt_hci_driver structure.

BT_HCI_SETUP feature is useful when the BT Controller requires execution
of the vendor-specific commands sequence to initialize the BT Controller
before the BT Host executes a Reset sequence. To enable this feature the
CONFIG_BT_HCI_SETUP should be enable.

Fixes #41140

Signed-off-by: Nazar Palamar <nazar.palamar@infineon.com>