xen: remove 4.8 recipe
xen: remove 4.8 recipe

We have 4.9 in the tree, so we no longer need the 4.8 variant.

Signed-off-by: Bruce Ashfield <284cc737d174a260eec2a2a6324a304f84b1ae0f@windriver.com>

lgirdk/meta-virtualization,lgirdk/meta-virtualization,lgirdk/meta-virtualization,lgirdk/meta-virtualization,lgirdk/meta-virtualization