flash: Make flash aboard with a useful error

Originally flash.sh would attempt to load a non-existant partition table
if it couldn't determine an appropriate eMMC size. This changes it to
error out with a useful message instead.

Change-Id: Ieefebce849f7dde19854caf4581c24807fe71efd
1 file changed
tree: 497ab1ccc03676049663d6743f8c8248ad9879e9
  1. boot.txt
  2. defconfig
  3. flash.sh
  4. fstab.emmc
  5. fstab.sdcard
  6. partition-table.json