Bluetooth: Add tty HCI driver

tty_hci driver exposes a /dev/hci_tty character device node, that intends to
emulate a generic /dev/ttyX device that would be used by the user-space
Bluetooth stacks to send/receive data to/from the WL combo-connectivity
chipsets.

The device driver has no internal logic of its own to intrepret data & all
such logic is handled by the user-space stack.

Change-Id: Ifa3860bbc7e252af210fde710bce14143239b552
Signed-off-by: Pavan Savoy <pavan_savoy@ti.com>
[steven@steven676.net: make apply to 3.0]
encore_defconfig: add TI hci_tty driver for Android >= 4.2 BT support
encore_defconfig: enable CONFIG_LOCALVERSION_AUTO

This will put the SHA1 hash of the commit from which the kernel is built
into the version string, making it much easier to pinpoint the exact
source code associated with a particular bug report.  CONFIG_MODVERSIONS
(already enabled) means this change won't break kernel module
compatibility unnecessarily.
Add a separate defconfig for CM 10.1/Android 4.2 builds

The 10.1 buildconfig has CONFIG_PANEL_BOXER_TRUE_COLOR=y and
CONFIG_ST_HCI=y set.  Meanwhile, remove CONFIG_ST_HCI from
encore_defconfig, since it's not needed on Android < 4.2.