staging: kpc2000: Fix: 'kpc_dma_del_device' and other symbols were not declared

This patch removes the Sparse generated warnings. Following warnings are reported by Sparse:
drivers/staging/kpc2000//kpc_dma/kpc_dma_driver.c:46:6: warning: symbol 'kpc_dma_del_device' was not declared. Should it be static?
drivers/staging/kpc2000//kpc_dma/kpc_dma_driver.c:91:14: warning: symbol 'kpc_dma_class' was not declared. Should it be static?
drivers/staging/kpc2000//kpc_dma/kpc_dma_driver.c:199:24: warning: symbol 'kpc_dma_plat_driver_i' was not declared. Should it be static?
Signed-off-by: Rishiraj Manwatkar <manwatkar@outlook.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/kpc2000/kpc_dma/kpc_dma_driver.c

@@ -43,7 +43,7 @@ static void kpc_dma_add_device(struct kpc_dma_device *ldev)
 	mutex_unlock(&kpc_dma_mtx);
 }
 
-void kpc_dma_del_device(struct kpc_dma_device *ldev)
+static void kpc_dma_del_device(struct kpc_dma_device *ldev)
 {
 	mutex_lock(&kpc_dma_mtx);
 	list_del(&ldev->list);
@@ -88,7 +88,7 @@ static const struct attribute *ndd_attr_list[] = {
 	NULL,
 };
 
-struct class *kpc_dma_class;
+static struct class *kpc_dma_class;
 
 /**********  Platform Driver Functions  **********/
 static
@@ -192,7 +192,7 @@ int  kpc_dma_remove(struct platform_device *pldev)
 }
 
 /**********  Driver Functions  **********/
-struct platform_driver kpc_dma_plat_driver_i = {
+static struct platform_driver kpc_dma_plat_driver_i = {
 	.probe        = kpc_dma_probe,
 	.remove       = kpc_dma_remove,
 	.driver = {