ASPEED AST2700 SOC is a 64 bits quad core CPUs (Cortex-a35)
and the base address of dram is "0x4 00000000" which
is 64bits address.
It has "Master DMA Mode Tx Buffer Base Address[39:32](0x60)"
and "Master DMA Mode Rx Buffer Base Address[39:32](0x64)"
registers to save the high part physical address of Tx/Rx
buffer address for master mode.
It has "Slave DMA Mode Tx Buffer Base Address[39:32](0x68)" and
"Slave DMA Mode Rx Buffer Base Address[39:32](0x6C)" registers
to save the high part physical address of Tx/Rx buffer address
for slave mode.
Ex: Tx buffer address for master mode [39:0]
The "Master DMA Mode Tx Buffer Base Address[39:32](0x60)"
bits [7:0] which corresponds the bits [39:32] of the 64 bits address of
the Tx buffer address.
The "Master DMA Mode Tx Buffer Base Address(0x30)" bits [31:0]
which corresponds the bits [31:0] of the 64 bits address
of the Tx buffer address.
Introduce a new has_dma64 class attribute and new registers for the
new mode to support DMA 64 bits dram address.
Update new mode register number to 28.
The aspeed_i2c_bus_vmstate is changed again and
version is not increased because it was done earlier in the same series.
Signed-off-by: Jamin Lin <jamin_lin@aspeedtech.com>