[PATCH] Add ff-memless-next module

[Michal Malý]

This patch adds "ff-memless-next" module. This module is based on the current
"ff-memless" module but it has considerably extended capabilities. These include:

- Support for periodic and conditional effects
- Support for ramp effect
- Variable update time

Why is this written as a new module and not a patch for "ff-memless"? This
module uses a different API for the HW-specific driver; this was a necessary
step to make use of the module's additional features. All 25 drivers that
currently use "ff-memless" would have to be updated. "ff-memless-next" currently
does not support FF_RUMBLE which is needed to support various joypads. My
intention is to:
1) Port hid-lg4ff driver for Logitech gaming wheels to "ff-memless-next" API to
   test the module with real hardware.
2) Add support for FF_RUMBLE and information reporting about effect's status
   changes identical to that in iforce driver.
3) Gradually port other drivers to "ff-memless-next".
4) Fully replace "ff-memless" with "ff-memless-next".

Because of the scope of the changes I am concerned about breaking functionality
of devices that are currently working perfectly fine with "ff-memless" which is
why I'd like to make the move towards "ff-memless-next" a gradual process.

Tested-by: Elias Vanderstuyft <elias.vds@xxxxxxxxx>
Signed-off-by: Michal Malý <madcatxster@xxxxxxxxx>
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