Finally created my own recipe that "require recipes-kernel/linux/linux-yocto.inc":
Own defconfig and support of fragments, warrior branch, no use of Freescale BSP, just clone poky and meta-openembedded. Simple and efficient.
DESCRIPTION = "Linux Kernel for SoMLabs boards"
SECTION = "kernel"
LICENSE = "GPLv2"
LIC_FILES_CHKSUM = "file://COPYING;md5=d7810fab7487fb0aad327b76f1be7cd7"
COMPATIBLE_MACHINE = "sls16y2_792c_512r_512n_1wb"
require recipes-kernel/linux/linux-yocto.inc
DEPENDS += "lzop-native bc-native"
SRCBRANCH = "imx_4.9.123_imx8mm_ga"
LOCALVERSION = "-imx"
SRCREV = "6a71cbc089755afd6a86c005c22a1af6eab24a70"
SRC_URI += " \
git://source.codeaurora.org/external/imx/linux-imx;protocol=git;branch=${SRCBRANCH} \
file://sls16y2_792c_512r_512n_1wb.dts \
file://defconfig \
"
LINUX_VERSION ?= "4.9.123"
PV = "${LINUX_VERSION}+git${SRCPV}"
S = "${WORKDIR}/git"
# Copy the right dts after unpack of the sources
python do_copydts () {
import shutil
src = ("%s/%s.dts" % (d.getVar('WORKDIR'), d.getVar('MACHINE')))
dst = ("%s/arch/%s/boot/dts/%s" % (d.getVar('S'), d.getVar('ARCH'), d.getVar('KERNEL_DEVICETREE').replace('dtb', 'dts')))
shutil.copy2(src, dst)
}
addtask do_copydts after do_unpack before do_patch