microblaze/PCI: Remove stale pcibios_align_resource() comment

commit 01cf9d52 ("microblaze/PCI: Support generic Xilinx AXI PCIe Host
Bridge IP driver")

and

commit ecf677c8 ("PCI: Add a generic weak pcibios_align_resource()")

first patched then removed pcibios_align_resource() from the microblaze
architecture code but failed to remove the comment that was added to
it.

Remove it since it has now become stale and it is quite confusing.

Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Bharat Kumar Gogada <bharatku@xilinx.com>
Cc: Michal Simek <monstr@monstr.eu>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>