imx6: use more common name for ubi(fs) images

Signed-off-by: Luka Perkov <luka@openwrt.org>

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@38520 3c298f89-4303-0410-b956-a3cf2f4a3e73
imx6: use more descriptive function name

Signed-off-by: Luka Perkov <luka@openwrt.org>

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@38521 3c298f89-4303-0410-b956-a3cf2f4a3e73
imx6: ventana boards use kmod-sky2

Signed-off-by: Luka Perkov <luka@openwrt.org>

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@38522 3c298f89-4303-0410-b956-a3cf2f4a3e73