[COMMON] g2d: support secure mode

[COMMON] g2d: support secure mode

Support to blend the secure layer. To access the secure layer,
it must enable secure mode of G2D from secure world,
and command area must be mapped to secure mmu.

When both normal and secure tasks are running at the same time
on H/W queue, confilcts could be occurred by turning on/off
the secure mode, which reads the command area from
secure or normal sysmmu.

So, always turn on the secure mode and map the command to
secure mmu.

Change-Id: Ia15796e611a9b6f98181183c556d4f4848fa455e
Signed-off-by: hyesoo.yu <hyesoo.yu@samsung.com>