Fixed compiler warning in v-boot reference.
Fixed compiler warning in v-boot reference.

The error was:
  arch/arm/lib/crossystem_arch.c: In function ‘VbReadSharedMemory’:
  arch/arm/lib/crossystem_arch.c:134: error: format ‘%d’ expects type ‘int’, but argument 5 has type ‘long unsigned int’

BUG=none
TEST=(outside choot): cd src/platform/vboot_reference; make

Change-Id: I5e1f69abd125fe06cf6ae04a7946568bdbcef83e
Reviewed-on: http://gerrit.chromium.org/gerrit/1547
Tested-by: Doug Anderson <49983c4a76b998672954ed5edf4a62db4a336502@chromium.org>
Reviewed-by: Bill Richardson <129945214b1d548d8e49b6c29c43094f8c78057f@chromium.org>

geekboxzone/mmallow_external_vboot_reference,ionave/seismograph,acorn-marvell/vboot_reference,geekboxzone/mmallow_external_vboot_reference,geekboxzone/mmallow_external_vboot_reference,marineam/seismograph,marineam/seismograph,geekboxzone/mmallow_external_vboot_reference,marineam/seismograph,coreboot/vboot,coreboot/vboot,ccaapton/vboot_reference,coreboot/vboot,acorn-marvell/vboot_reference,coreboot/vboot,acorn-marvell/vboot_reference,ccaapton/vboot_reference,geekboxzone/mmallow_external_vboot_reference,ccaapton/vboot_reference,acorn-marvell/vboot_reference,coreboot/vboot,ionave/seismograph,marineam/seismograph,ionave/seismograph,ccaapton/vboot_reference