regmap: mmio: Staticize regmap_mmio_gen_context()

regmap_mmio_gen_context() is only used in regmap-mmio.c. Thus make it static.
Signed-off-by: Axel Lin <axel.lin@gmail.com>
Acked-by: Stephen Warren <swarren@wwwdotorg.org>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

drivers/base/regmap/regmap-mmio.c

@@ -128,7 +128,7 @@ static struct regmap_bus regmap_mmio = {
 	.val_format_endian_default = REGMAP_ENDIAN_NATIVE,
 };
 
-struct regmap_mmio_context *regmap_mmio_gen_context(void __iomem *regs,
+static struct regmap_mmio_context *regmap_mmio_gen_context(void __iomem *regs,
 					const struct regmap_config *config)
 {
 	struct regmap_mmio_context *ctx;