powerpc/85xx: add alternate dts file for sbc8548 boot via SODIMM

By moving the two JP12 jumpers 90 degrees, and switching the
setting of SW2.8, the sbc8548 can be configured to boot off
the alternate 64MB SODIMM, which when populated with u-boot
can be a handy recovery option, in case the u-boot in the
8MB soldered on flash gets corrupted.  Here we add an alternate
dts file to match that configuration.

To better highlight the differences, the output from the u-boot
"fli" command is shown for the normal configuration and then
the alternate configuration.

Normal:
 -----------------------
Bank # 1: CFI conformant flash (8 x 8)  Size: 8 MB in 64 Sectors
  Intel Extended command set, Manufacturer ID: 0x89, Device ID: 0x17
  Erase timeout: 4096 ms, write timeout: 1 ms
  Buffer write timeout: 2 ms, buffer size: 32 bytes

  Sector Start Addresses:
  FF800000 E      FF820000 E      FF840000 E      FF860000 E      FF880000 E
 [...]
  FFEE0000 E      FFF00000 E      FFF20000 E      FFF40000 E      FFF60000 E
  FFF80000        FFFA0000   RO   FFFC0000   RO   FFFE0000   RO

Bank # 2: CFI conformant flash (32 x 8)  Size: 64 MB in 128 Sectors
  Intel Extended command set, Manufacturer ID: 0x89, Device ID: 0x18
  Erase timeout: 4096 ms, write timeout: 1 ms
  Buffer write timeout: 2 ms, buffer size: 32 bytes

  Sector Start Addresses:
  EC000000 E      EC080000 E      EC100000 E      EC180000 E      EC200000 E
 [...]
  EFC00000 E      EFC80000 E      EFD00000 E      EFD80000 E      EFE00000 E
  EFE80000 E      EFF00000        EFF80000
 -----------------------

Alternate:
 -----------------------
Bank # 1: CFI conformant flash (32 x 8)  Size: 64 MB in 128 Sectors
  Intel Extended command set, Manufacturer ID: 0x89, Device ID: 0x18
  Erase timeout: 4096 ms, write timeout: 1 ms
  Buffer write timeout: 2 ms, buffer size: 32 bytes

  Sector Start Addresses:
  FC000000 E      FC080000 E      FC100000 E      FC180000 E      FC200000 E
 [...]
  FFC00000 E      FFC80000 E      FFD00000 E      FFD80000 E      FFE00000 E
  FFE80000 E      FFF00000   RO   FFF80000   RO

Bank # 2: CFI conformant flash (8 x 8)  Size: 8 MB in 64 Sectors
  Intel Extended command set, Manufacturer ID: 0x89, Device ID: 0x17
  Erase timeout: 4096 ms, write timeout: 1 ms
  Buffer write timeout: 2 ms, buffer size: 32 bytes

  Sector Start Addresses:
  EF800000 E      EF820000 E      EF840000 E      EF860000 E      EF880000 E
 [...]
  EFEE0000 E      EFF00000 E      EFF20000 E      EFF40000 E      EFF60000 E
  EFF80000 E      EFFA0000        EFFC0000        EFFE0000
 -----------------------

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>