Staging: add Synaptics TM1217 Touchscreen Controller driver

This is submitted as a staging driver because there is a more generic driver
"on the way" for all these devices and has been for some time. The intent is
that as soon as the general drivers are in the mainstream this one will get
any leftovers integrated and then be dumped. Until this unspecified future
data at least people can actually use their hardware.

As its interface is simply input layer we can do that without pain.

Some clean up by Alan Cox
  - Extract gpio support and IRQ support more sanely
  - Tidying

Signed-off-by: Ramesh Agarwal <ramesh.agarwal@intel.com>
[avoid deference NULL ts if kzalloc fails]
[finger_touched may be used uninitialized]
[fix missing sync which confused twm]
Signed-off-by: Hong Liu <hong.liu@intel.com>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>