arm: a37xx: pci: Increase PCIe MEM size from 16 MiB to 127 MiB

For some configurations with more PCIe cards and PCIe bridges, 16 MiB of
PCIe MEM space may not be enough. Since TF-A already allocates a 128 MiB
CPU window for PCIe, and since IO port space is only 64 KiB in total,
use all the remaining space (64 + 32 + 16 + 8 + 4 + 2 + 1 = 127 MiB) for
PCIe MEM.

Signed-off-by: Pali Rohár <pali@kernel.org>
Reviewed-by: Marek Behún <marek.behun@nic.cz>
Reviewed-by: Stefan Roese <sr@denx.de>