generic: remove patch to fix vlan setup on mv88e6xxx

This patch was present in Linux kernel [1] since version 5.11rc1, but it
was superseded by another patch, which set configure_vlan_while_not_filtering
to true by default since kernel v5.12-rc2 [2].

[1] https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/drivers/net/dsa/mv88e6xxx/chip.c?h=v5.15.41&id=b8b79c414eca4e9bcab645e02cb92c48db974ce9

[2] torvalds/linux@0ee2af4

Signed-off-by: Josef Schlehofer <pepe.schlehofer@gmail.com>