meta-openembedded: Avoid stale SPDX reference with kernel dependency

mdio-tools and its relationship with mdio-netlink and the mdio-netlink
kernel module breaks SPDX processing while generating the rootfs after a
kernel bump. For example:

    ERROR: obmc-phosphor-image-1.0-r0 do_rootfs: Cannot find any SPDX file for document http://spdx.org/spdxdoc/kernel-module-mdio-netlink-6.5.4-da279e9-00089-gda279e98c07f-89187488-3164-50cb-94c5-8b76a30ea093
    ERROR: Logfile of failure stored in: /home/andrew/src/openbmc.org/openbmc/openbmc/build/bletchley/tmp/work/bletchley-openbmc-linux-gnueabi/obmc-phosphor-image/1.0/temp/log.do_rootfs.262744
    ERROR: Task (/home/andrew/src/openbmc.org/openbmc/openbmc/meta-phosphor/recipes-phosphor/images/obmc-phosphor-image.bb:do_rootfs) failed with exit code '1'

In this case the error occurred after the following patch was applied:

    diff --git a/meta-aspeed/recipes-kernel/linux/linux-aspeed_git.bb b/meta-aspeed/recipes-kernel/linux/linux-aspeed_git.bb
    index e6f98297c540..b852e993f0f6 100644
    --- a/meta-aspeed/recipes-kernel/linux/linux-aspeed_git.bb
    +++ b/meta-aspeed/recipes-kernel/linux/linux-aspeed_git.bb
    @@ -1,6 +1,6 @@
     KBRANCH ?= "dev-6.5"
    -LINUX_VERSION ?= "6.5.4"
    +LINUX_VERSION ?= "6.5.9"

    -SRCREV="da279e98c07f9c948c60a434ab0043a55c26ea1d"
    +SRCREV="fc8d4fdba5bd2b9b1cea2aa8a731531943c45aa7"

     require linux-aspeed.inc

With the lack of a dependency the mdio-tools package is not rebuilt
subsequent to the kernel bump and the package information remains stale,
leading to an incorrect spdx path being generated.

Change-Id: I6b60300a61a1d7e33e304fa9fced1ac281a63c2a
Signed-off-by: Andrew Jeffery <andrew@codeconstruct.com.au>
diff --git a/meta-openembedded/meta-networking/recipes-support/mdio-tools/mdio-tools_1.3.0.bb b/meta-openembedded/meta-networking/recipes-support/mdio-tools/mdio-tools_1.3.0.bb
index cd4df3d..0c64889 100644
--- a/meta-openembedded/meta-networking/recipes-support/mdio-tools/mdio-tools_1.3.0.bb
+++ b/meta-openembedded/meta-networking/recipes-support/mdio-tools/mdio-tools_1.3.0.bb
@@ -1,6 +1,6 @@
 require mdio-tools.inc
 
-DEPENDS += "libmnl"
+DEPENDS += "virtual/kernel libmnl"
 
 S = "${WORKDIR}/git"