sfc: Add GFP flags to efx_nic_alloc_buffer() and make most callers allow blocking

Most call sites for efx_nic_alloc_buffer() are part of the probe or
reconfiguration paths and can allocate with GFP_KERNEL.  A few others
should use GFP_NOIO (I think).  Only one is in atomic context and
must use the current GFP_ATOMIC.

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
diff --git a/drivers/net/ethernet/sfc/nic.h b/drivers/net/ethernet/sfc/nic.h
index c699203..9120e8b 100644
--- a/drivers/net/ethernet/sfc/nic.h
+++ b/drivers/net/ethernet/sfc/nic.h
@@ -332,7 +332,7 @@
 extern void efx_nic_push_rx_indir_table(struct efx_nic *efx);
 
 int efx_nic_alloc_buffer(struct efx_nic *efx, struct efx_buffer *buffer,
-			 unsigned int len);
+			 unsigned int len, gfp_t gfp_flags);
 void efx_nic_free_buffer(struct efx_nic *efx, struct efx_buffer *buffer);
 
 /* Tests */