ARM: io: remove IO_SPACE_LIMIT from platforms with ISA/PCI and 64K window

Remove IO_SPACE_LIMIT definitions from platforms which have a well
defined ISA or PCI, and has a 64K window.

EBSA110 - well defined set of ISA devices.
Footbridge, Integrator, IXP4xx, VT8500 - PCI platforms.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>