arm: a9mpcore: remove un-used ptimer_iomem field

I'm guessing this is a hangover from a previous coreification of the mptimer
sub-module. This field is completely unused - removed.
Signed-off-by: NPeter Crosthwaite <peter.crosthwaite@xilinx.com>
Reviewed-by: NPeter Maydell <peter.maydell@linaro.org>
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>

hw/a9mpcore.c

@@ -19,7 +19,6 @@ typedef struct a9mp_priv_state {
     uint32_t old_timer_status[8];
     uint32_t num_cpu;
     MemoryRegion scu_iomem;
-    MemoryRegion ptimer_iomem;
     MemoryRegion container;
     DeviceState *mptimer;
     DeviceState *gic;