ARM: mmp: register internal sram bank

ARM: mmp: register internal sram bank

MMP2 have the internal sram, this sram can be allocated
for video, power management and secure processor.

Now the sram usage is:
0xd1000000 ~ 0xd101ffff (128KB) : reserved for secure processor
0xd1020000 ~ 0xd1037fff (96KB)  : for video and PM

Register the internal sram's second half 96KB buffer,
so that video and PM can dynamically alloc/free from it.

Signed-off-by: Leo Yan <[email protected]>
Acked-by: Haojian Zhuang <[email protected]>
Signed-off-by: Eric Miao <[email protected]>