pinctrl: pinctrl-microchip-sgpio: Mark some symbols with static keyword

Fix the following sparse warnings:

drivers/pinctrl/pinctrl-microchip-sgpio.c:63:31: warning: symbol 'properties_luton' was not declared. Should it be static?
drivers/pinctrl/pinctrl-microchip-sgpio.c:68:31: warning: symbol 'properties_ocelot' was not declared. Should it be static?
drivers/pinctrl/pinctrl-microchip-sgpio.c:73:31: warning: symbol 'properties_sparx5' was not declared. Should it be static?
Signed-off-by: Zou Wei <zou_wei@huawei.com>
Link: https://lore.kernel.org/r/1606218173-3722-1-git-send-email-zou_wei@huawei.comSigned-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/pinctrl/pinctrl-microchip-sgpio.c

@@ -60,17 +60,17 @@ struct sgpio_properties {
 #define SGPIO_SPARX5_CLK_FREQ    GENMASK(19, 8)
 #define SGPIO_SPARX5_BIT_SOURCE  GENMASK(23, 12)
 
-const struct sgpio_properties properties_luton = {
+static const struct sgpio_properties properties_luton = {
 	.arch   = SGPIO_ARCH_LUTON,
 	.regoff = { 0x00, 0x09, 0x29, 0x2a, 0x2b },
 };
 
-const struct sgpio_properties properties_ocelot = {
+static const struct sgpio_properties properties_ocelot = {
 	.arch   = SGPIO_ARCH_OCELOT,
 	.regoff = { 0x00, 0x06, 0x26, 0x04, 0x05 },
 };
 
-const struct sgpio_properties properties_sparx5 = {
+static const struct sgpio_properties properties_sparx5 = {
 	.arch   = SGPIO_ARCH_SPARX5,
 	.regoff = { 0x00, 0x06, 0x26, 0x04, 0x05 },
 };