misc: ti_drv2667: Add support for DRV2667 controller

TI's DRV2667 controller is used for driving haptics.
It can operate in two modes - analog and digital. The
first version of the driver supports only digital mode.

Change-Id: I448d8b34d4ad1b2500e5a4d0973cfc5b22515d5a
Signed-off-by: Mohan Pallaka <mpallaka@codeaurora.org>
[stepanm@codeaurora.org: fix Makefile conflicts]
Signed-off-by: Stepan Moskovchenko <stepanm@codeaurora.org>