PCI: dwc: al: Add Amazon Annapurna Labs PCIe controller driver

This driver is DT based and utilizes the DesignWare APIs.

It allows using a smaller ECAM range for a larger bus range -
usually an entire bus uses 1MB of address space, but the driver
can use it for a larger number of buses. This is achieved by using a HW
mechanism which allows changing the BUS part of the "final" outgoing
config transaction. There are 2 HW regs, one which is basically a
bitmask determining which bits to take from the AXI transaction itself
and another which holds the complementary part programmed by the
driver.

All link initializations are handled by the boot FW.

Signed-off-by: Jonathan Chocron <jonnyc@amazon.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Gustavo Pimentel <gustavo.pimentel@synopsys.com>
Reviewed-by: Andrew Murray <andrew.murray@arm.com>