kernel-devsrc: fix arm/arm64 target module build

kernel-devsrc: fix arm/arm64 target module build

module.lds is required for arch/arm* to build modules out of tree, but
isn't required for scripts/prepare, so it was missed in the initial
devsrc rework:

root@qemuarm64:/tmp# make -C /usr/src/kernel M=/tmp modules
make: Entering directory '/lib/modules/4.18.3-yocto-standard/build'
  CC [M]  /tmp/hellomod.o
  Building modules, stage 2.
  MODPOST 1 modules
  CC      /tmp/hellomod.mod.o
  LD [M]  /tmp/hellomod.ko
make: Leaving directory '/lib/modules/4.18.3-yocto-standard/build'
root@qemuarm64:/tmp# insmod hellomod.ko
[  675.743628] hellomod: loading out-of-tree module taints kernel.
[  675.794959] Hello world!

Signed-off-by: Bruce Ashfield <bruce.ashfield@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>