regmap: constify regmap_bus structures

These regmap_bus structures are only passed as the second argument to
__devm_regmap_init or __regmap_init, both of which are const, so the
regmap_bus structures can be const too.

Done with the help of Coccinelle.
Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Mark Brown <broonie@kernel.org>

drivers/base/regmap/regmap-spi.c

@@ -102,7 +102,7 @@ static int regmap_spi_read(void *context,
 	return spi_write_then_read(spi, reg, reg_size, val, val_size);
 }
 
-static struct regmap_bus regmap_spi = {
+static const struct regmap_bus regmap_spi = {
 	.write = regmap_spi_write,
 	.gather_write = regmap_spi_gather_write,
 	.async_write = regmap_spi_async_write,

drivers/base/regmap/regmap-spmi.c

@@ -83,7 +83,7 @@ static int regmap_spmi_base_write(void *context, const void *data,
 					     count - 1);
 }
 
-static struct regmap_bus regmap_spmi_base = {
+static const struct regmap_bus regmap_spmi_base = {
 	.read				= regmap_spmi_base_read,
 	.write				= regmap_spmi_base_write,
 	.gather_write			= regmap_spmi_base_gather_write,
@@ -203,7 +203,7 @@ static int regmap_spmi_ext_write(void *context, const void *data,
 					    count - 2);
 }
 
-static struct regmap_bus regmap_spmi_ext = {
+static const struct regmap_bus regmap_spmi_ext = {
 	.read				= regmap_spmi_ext_read,
 	.write				= regmap_spmi_ext_write,
 	.gather_write			= regmap_spmi_ext_gather_write,