hw/arm/armsse: Give each CPU its own view of memory

hw/arm/armsse: Give each CPU its own view of memory

Give each CPU its own container memory region. This is necessary
for two reasons:
 * some devices are instantiated one per CPU and the CPU sees only
   its own device
 * since a memory region can only be put into one container, we must
   give each armv7m object a different MemoryRegion as its 'memory'
   property, or a dual-CPU configuration will assert on realize when
   the second armv7m object tries to put the MR into a container when
   it is already in the first armv7m object's container

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20190121185118.18550-13-peter.maydell@linaro.org