Create SOC_DEFAULT_IMAGE_FSTYPES variable with default IMAGE_FSTYPES
used by all QorIQ targets. Default FSTYPES are tar.gz, ext2.gz.u-boot
and ext2.gz.
The IMAGE_FSTYPES need to be overriden without using the SoC family
overrides, for user-friendness, and to allow this we need to use a SoC
variable to construct the default value for setting.
Signed-off-by: Fabio Berton <fabio.berton@ossystems.com.br> Signed-off-by: Otavio Salvador <otavio@ossystems.com.br>