[ARM] Simplify twd_clockchip_init() for local timers

Signed-off-by: Anup Patel <anup@brainfault.org>
[CORE] Update bootup sequence to justify meaning of arch_cpu_early_init() and arch_board_early_init()

We cannot have meaningful code in arch_cpu_early_init() and arch_board_early_init() with just host aspace and heap APIs.

The actual intention behind arch_cpu_early_init() and arch_board_early_init() is to have early iomappings, system device init, clocking init, etc.

This patch restores intended meaning of arch_cpu_early_init() and arch_board_early_init() by initializing host aspace, heap, device tree, and host irq before these early functions. This way we can also use device tree and host irq APIs in early init functions.

This patch also fixes device tree init and ACPI table init for Xvisor x86_64 to ensure x86_64 bootup sequence don't break.

Signed-off-by: Anup Patel <anup@brainfault.org>
[DRIVERS] amba-clcd: Fix compatible matching string

Signed-off-by: Anup Patel <anup@brainfault.org>
[DRIVERS] rework clk.h linux compatibility header file.

Signed-off-by: Anup Patel <anup@brainfault.org>
[CORE] vmm_devdrv.h: remove unecessry forward definition.

Signed-off-by: Anup Patel <anup@brainfault.org>
[CORE] vmm_devdrv.c: remove unecessary blanck space at end of line

Signed-off-by: Anup Patel <anup@brainfault.org>
[DRIVERS] Add clkdev API (2nd version).

Signed-off-by: Anup Patel <anup@brainfault.org>
[ARM] realview: Lookup device tree nodes using compatible string

Signed-off-by: Anup Patel <anup@brainfault.org>
[ARM] realview: Find GIC node based on compatible string

Signed-off-by: Anup Patel <anup@brainfault.org>
[ARM] vexpress-a9: Fix SCU compatible string

Signed-off-by: Anup Patel <anup@brainfault.org>
[ARM] vexpress-a15: Fix compatible string for GIC

Signed-off-by: Anup Patel <anup@brainfault.org>
[ARM] vexpress: Lookup device tree nodes using compatible string

Signed-off-by: Anup Patel <anup@brainfault.org>
[DRIVERS] clk: Make clock lookup API selectable.

Signed-off-by: Anup Patel <anup@brainfault.org>
[ARM] versatile: Lookup device tree nodes using compatible string

Signed-off-by: Anup Patel <anup@brainfault.org>
[ARM] sun4i: Lookup device tree nodes using compatible string

Signed-off-by: Anup Patel <anup@brainfault.org>
[CORE] vcpu state is now changed by vmm_scheduler_state_change()

vmm_scheduler_state_change() was renamed from
vmm_scheduler_notify_state_change()

Signed-off-by: Anup Patel <anup@brainfault.org>
Merge remote-tracking branch 'upstream/master'