Bluetooth: controller: fix compile error when VS cmds disabled

When vendor specific commands are disabled by setting
BT_HCI_VS=n the host still calls bt_read_static_addr,
but that function is not compiled in, resulting in a
build error.
Fixed by moving the code in controller/hci/hci.c
outside of the conditional compile

Signed-off-by: Andries Kruithof <andries.kruithof@nordicsemi.no>