net: sfc: Use GFP_KERNEL in efx_ef10_try_update_nic_stats()

efx_ef10_try_update_nic_stats_vf() is now only invoked from thread context
and can sleep after efx::stats_lock is dropped.

Change the allocation mode from GFP_ATOMIC to GFP_KERNEL.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>