exec: eliminate io_mem_ram It is never used, the IOTLB always goes through io_mem_notdirty. In fact in softmmu_template.h, if it were, QEMU would crash just below the tests, as soon as io_mem_read/write dispatches to error_mem_read/write. Reviewed-by: Richard Henderson <rth@twiddle.net> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>