sfc: Const-qualify static data as appropriate, partly prompted by checkpatch

Fix the following warnings:

WARNING: struct dev_pm_ops should normally be const
WARNING: static const char * array should probably be static const char * const

Similarly const-qualify struct i2c_board_info, struct i2c_algo_bit_data,
struct efx_ethtool_stat, struct efx_mtd_ops and struct siena_nvram_type_info.

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
diff --git a/drivers/net/ethernet/sfc/falcon.c b/drivers/net/ethernet/sfc/falcon.c
index 8ae1ebd..5c75489 100644
--- a/drivers/net/ethernet/sfc/falcon.c
+++ b/drivers/net/ethernet/sfc/falcon.c
@@ -89,7 +89,7 @@
 	return EFX_OWORD_FIELD(reg, FRF_AB_GPIO0_IN);
 }
 
-static struct i2c_algo_bit_data falcon_i2c_bit_operations = {
+static const struct i2c_algo_bit_data falcon_i2c_bit_operations = {
 	.setsda		= falcon_setsda,
 	.setscl		= falcon_setscl,
 	.getsda		= falcon_getsda,