avtimer: Add compat ioctl support for avtimer

If userspace is 32 bit and kernel is in 64 bit mode, ioctls for avtimer
will be called via the compat mode. Change adds support for compat ioctl
avtimer driver.

Change-Id: I8bf44f57efdc6069ea7c8badc8049c4b6b6e4eb5
Signed-off-by: Gopikrishnaiah Anandan <agopik@codeaurora.org>