vl-android.c: Support EXT4 cache partitions.

Kernel 3.10 dropped support for yaffs2 partitions, which forces
the cache partition to be ext4 too, just like the system and
data one.

This patch refactors the code in vl-android.c that configures
the NAND devices corresponding to each partition image to do
the following:

- Use a single function to perform the configuration, based
  on a small set of parameters (android_nand_add_device).

- Ensure that the cache partition uses 'ext4' if kernel 3.10
  or higher is used, or 'yaffs2' otherwise.

Change-Id: I7352dc436d5677c508b89591d92c066b4227ce3a
1 file changed