kernel: mtdsplit: modify rootfs helpers to provide partition type

Our mtdsplit parsers may want to create partition with name choice based
on partition file system (e.g. SquashFS vs. JFFS2). This patch allows
passing extra argument pointing to variable that will be set properly.

Signed-off-by: Rafał Miłecki <zajec5@gmail.com>

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@48598 3c298f89-4303-0410-b956-a3cf2f4a3e73

kernel: mtdsplit: add support for FIT image

If this option is enabled, the FIT image format will be detected and
split by the mtdsplit code. Detection is based upon the FDT magic, which
will trigger the parsing and detection of the rootfs, ending-up in the
creation of the 2 new partitions.

Signed-off-by: Mathieu Olivari <mathieu@codeaurora.org>

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@44792 3c298f89-4303-0410-b956-a3cf2f4a3e73