openvswitch: Move ovs_frag_data_storage into the struct ovs_pcpu_storage

ovs_frag_data_storage is a per-CPU variable and relies on disabled BH for its
locking. Without per-CPU locking in local_bh_disable() on PREEMPT_RT
this data structure requires explicit locking.

Move ovs_frag_data_storage into the struct ovs_pcpu_storage which already
provides locking for the structure.

Cc: Aaron Conole <aconole@redhat.com>
Cc: Eelco Chaudron <echaudro@redhat.com>
Cc: Ilya Maximets <i.maximets@ovn.org>
Cc: dev@openvswitch.org
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Aaron Conole <aconole@redhat.com>
Link: https://patch.msgid.link/20250512092736.229935-10-bigeasy@linutronix.de


Signed-off-by: Paolo Abeni <pabeni@redhat.com>