platform/x86: mlx-platform: make a couple of structures static

The structures mlxplat_dev and mlxplat_hotplug are local to the source
and do not need to be in global scope, so make them static.

Cleans up sparse warnings:
symbol 'mlxplat_dev' was not declared. Should it be static?
symbol 'mlxplat_hotplug' was not declared. Should it be static?
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Darren Hart (VMware) <dvhart@infradead.org>

drivers/platform/x86/mlx-platform.c

@@ -216,8 +216,8 @@ static struct resource mlxplat_mlxcpld_resources[] = {
 	[0] = DEFINE_RES_IRQ_NAMED(17, "mlxcpld-hotplug"),
 };
 
-struct platform_device *mlxplat_dev;
-struct mlxcpld_hotplug_platform_data *mlxplat_hotplug;
+static struct platform_device *mlxplat_dev;
+static struct mlxcpld_hotplug_platform_data *mlxplat_hotplug;
 
 static int __init mlxplat_dmi_default_matched(const struct dmi_system_id *dmi)
 {