arm64: Kernel booting and initialisation

arm64: Kernel booting and initialisation

The patch adds the kernel booting and the initial setup code.
Documentation/arm64/booting.txt describes the booting protocol on the
AArch64 Linux kernel. This is subject to change following the work on
boot standardisation, ACPI.

Signed-off-by: Will Deacon <[email protected]>
Signed-off-by: Catalin Marinas <[email protected]>
Acked-by: Nicolas Pitre <[email protected]>
Acked-by: Tony Lindgren <[email protected]>
Acked-by: Olof Johansson <[email protected]>
Acked-by: Santosh Shilimkar <[email protected]>
Acked-by: Arnd Bergmann <[email protected]>