Now that the only field in struct sys_timer is .init, delete the struct,
and replace the machine descriptor .timer field with the initialization
function itself.

This will enable moving timer drivers into drivers/clocksource without
having to place a public prototype of each struct sys_timer object into
include/linux; the intent is to create a single of_clocksource_init()
function that determines which timer driver to initialize by scanning
the device dtree, much like the proposed irqchip_init() at:
http://www.spinics.net/lists/arm-kernel/msg203686.html

Includes mach-omap2 fixes from Igor Grinberg.
Tested-by: NRobert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: NStephen Warren <swarren@nvidia.com>

This gets rid of the separate u300.c file in mach-u300 since
it can just as well live right in core.c, then we also get
rid of the broadcasted <mach/platform.h> file that is not
helping anyone. Put the interface to the system timer into
a separate header.
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>