[U-Boot] ARMv8/FSL_LSCH3: SoC and board support

[York Sun]

[Patch v2 1/5] Added 64-bit MMIO accessors for ARMv8
[Patch v2 2/5] ARMv8/FSL_LSCH3: Add FSL_LSCH3 SoC
[Patch v2 3/5] ARMv8/ls2100a_emu: Add LS2100A emulator board support
[Patch v2 4/5] armv8/fsl-lsch3: Add support to load and start MC
[Patch v2 5/5] fsl-lsch3/ls2100a_emu: Enabled MC

I have sent 2/5 as individual patch before. To avoid confusion, let's
start with v2.

Change since v1:
 2/5 ARMv8/FSL_LSCH3: Add FSL_LSCH3 SoC
 Add L3 cache flushing
 Revised MMU table
 Re-create MMU in DDR after relocation
 Fix topology and clock registers

This set should be applied in order. I will create a bundle in patchwor to
include floating patches to show the dependency.

York