ARM: delete struct sys_timer

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: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Stephen Warren <swarren@nvidia.com>

arch/arm/mach-omap1/board-generic.c

@@ -84,6 +84,6 @@ MACHINE_START(OMAP_GENERIC, "Generic OMAP1510/1610/1710")
 	.init_irq	= omap1_init_irq,
 	.init_machine	= omap_generic_init,
 	.init_late	= omap1_init_late,
-	.timer		= &omap1_timer,
+	.init_time	= omap1_timer_init,
 	.restart	= omap1_restart,
 MACHINE_END