pinctrl: aspeed: Make aspeed_pinmux_ips static

Fix sparse warning:

drivers/pinctrl/aspeed/pinmux-aspeed.c:8:12: warning:
 symbol 'aspeed_pinmux_ips' was not declared. Should it be static?

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Link: https://lore.kernel.org/r/20190711142457.37028-1-yuehaibing@huawei.com
Reviewed-by: Andrew Jeffery <andrew@aj.id.au>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/pinctrl/aspeed/pinmux-aspeed.c

@@ -5,7 +5,7 @@
 
 #include "pinmux-aspeed.h"
 
-const char *const aspeed_pinmux_ips[] = {
+static const char *const aspeed_pinmux_ips[] = {
 	[ASPEED_IP_SCU] = "SCU",
 	[ASPEED_IP_GFX] = "GFX",
 	[ASPEED_IP_LPC] = "LPC",