ARM add initial support for the Phytium Pe2201 Board.

Add pe2201 platform code and the device tree of pe2201 platform board.
The initial support comprises the UART and PCIe.

Signed-off-by: TracyMg_Li <TracyMg_Li@outlook.com>
Changes since v1:
fix space corrupt.
Changes since v2:
switch to bootstd and text environment.
Changes since v3:
add environment variables.