ARM/PCI: Remove unused fields from struct hw_pci

ARM/PCI: Remove unused fields from struct hw_pci

The msi_ctrl, io_optional and align_resource fields in struct hw_pci are
currently unused by arm/mach PCI host controller drivers and we won't
be adding any new users.

Remove them and related code.

Link: https://lore.kernel.org/r/20200904141607.4066-1-lorenzo.pieralisi@arm.com
Link: https://lore.kernel.org/r/20200916103045.28651-1-lorenzo.pieralisi@arm.com
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Cc: Rob Herring <robh@kernel.org>
Cc: Russell King <linux@armlinux.org.uk>