Remove ioport specific routines

Now that all users of the dedicated ioport trap handler interface are
gone, we can retire the code associated with it.

This removes ioport.c and ioport.h, along with removing prototypes from
other header files.

This also transfers the responsibility for port I/O trap handling
entirely into the new routine in mmio.c.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com>
Link: https://lore.kernel.org/r/20210315153350.19988-20-andre.przywara@arm.com


Signed-off-by: Will Deacon <will@kernel.org>