UBUNTU: ubuntu: vbox: build fixes for 4.15

UBUNTU: ubuntu: vbox: build fixes for 4.15

This patch file makes the necessary changes to the VirtualBox 5.1.30 sources
to allow the kernel modules to build with kernel 4.15.

The API changes are of several types:

1. The timer initialization routine init_timer_pinned() no longer exists, and
   is replaced by timer_setup().
2. The timer callback routine calling sequence is changed as is the technique
   for getting the timer information from the callback parameters.
3. The calling sequence for drm_encoder_find() is changed.
4. The calling sequence for the .get and .set members of the module_param_call()
   calls have changed.

This patch is released under the MIT license when appropriate, GPLv2 otherwise.

Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>