linux-raspberrypi: Build dtbs with dtbs make target for rpi64

OE currently builds dtb files with its own custom targets by
specifying each dtb file as makefile target, this creates bad
dtb for rpi64 bit. This patch calles 'make dtbs' at the end
which regenerates the correct dtb files

This makes the vc4 initialize properly on rpi64

Signed-off-by: Khem Raj <raj.khem@gmail.com>

recipes-kernel/linux/linux-raspberrypi.inc

@@ -38,6 +38,11 @@ python __anonymous () {
     d.setVar("KERNEL_DEVICETREE", kerneldt)
 }
 
+do_compile_append_raspberrypi3-64() {
+    cc_extra=$(get_cc_option)
+    oe_runmake dtbs CC="${KERNEL_CC} $cc_extra " LD="${KERNEL_LD}" ${KERNEL_EXTRA_ARGS}
+}
+
 do_install_prepend() {
     install -d ${D}/lib/firmware
 }