exynos4210.c: register rom_mem for memory migration

exynos4210.c: register rom_mem for memory migration

Even if we do not register newly created RAM MemoryRegion for migration with
vmstate_register_ram_global() function, ram_save_setup() still saves this region
to snapshot file with empty idstr=="". Consequently this results in error during
VM loading in ram_load().
Register rom_mem for migration.

Signed-off-by: Igor Mitsyanko <i.mitsyanko@samsung.com>
Message-id: 1368199981-45292-3-git-send-email-i.mitsyanko@gmail.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>