msm: board-msm7x30: Fix for DDR1 memory configuration

In 7x30 device DDR1 Ram's 2nd bank starts from address
0x20000000 while in DDR2 Ram, start address is 0x40000000.
Hence physical offset for 2nd bank needs to be configured
depending on the address of 2nd bank. This offset is used
in virtual to physical address calculation and vice versa.

Hence add a machine fixup fuction, which at runtime
will find the address of 2nd bank and accordingly configure
the physical offset. So device with any memory configuration
will be able to boot.

CRs-Fixed: 326370
Change-Id: I094ca0fc17c50a85009c81169a57194b06f86456
Signed-off-by: Pankaj Kumar <pakuma@codeaurora.org>