[media] v4l2-ioctl.c: fix sparse __user-related warnings

Fix the use of __user in the check_array_args() prototype: instead of
using 'void * __user *' you should use 'void __user **' for sparse to
understand this correctly.

This also required the use of __force in the '*kernel_ptr = user_ptr'
assignment.

Also replace a wrong cast (void *) with the correct one (void **)
in check_array_args().

This fixes these sparse warnings:

drivers/media/v4l2-core/v4l2-ioctl.c:2284:35: warning: incorrect type in assignment (different address spaces)
drivers/media/v4l2-core/v4l2-ioctl.c:2301:35: warning: incorrect type in assignment (different address spaces)
drivers/media/v4l2-core/v4l2-ioctl.c:2319:35: warning: incorrect type in assignment (different address spaces)
drivers/media/v4l2-core/v4l2-ioctl.c:2386:57: warning: incorrect type in argument 4 (different address spaces)
drivers/media/v4l2-core/v4l2-ioctl.c:2420:29: warning: incorrect type in assignment (different address spaces)
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>

drivers/media/v4l2-core/v4l2-ioctl.c

@@ -2260,7 +2260,7 @@ static long __video_do_ioctl(struct file *file,
 }
 
 static int check_array_args(unsigned int cmd, void *parg, size_t *array_size,
-			    void * __user *user_ptr, void ***kernel_ptr)
+			    void __user **user_ptr, void ***kernel_ptr)
 {
 	int ret = 0;
 
@@ -2277,7 +2277,7 @@ static int check_array_args(unsigned int cmd, void *parg, size_t *array_size,
 				break;
 			}
 			*user_ptr = (void __user *)buf->m.planes;
-			*kernel_ptr = (void *)&buf->m.planes;
+			*kernel_ptr = (void **)&buf->m.planes;
 			*array_size = sizeof(struct v4l2_plane) * buf->length;
 			ret = 1;
 		}
@@ -2294,7 +2294,7 @@ static int check_array_args(unsigned int cmd, void *parg, size_t *array_size,
 				break;
 			}
 			*user_ptr = (void __user *)edid->edid;
-			*kernel_ptr = (void *)&edid->edid;
+			*kernel_ptr = (void **)&edid->edid;
 			*array_size = edid->blocks * 128;
 			ret = 1;
 		}
@@ -2312,7 +2312,7 @@ static int check_array_args(unsigned int cmd, void *parg, size_t *array_size,
 				break;
 			}
 			*user_ptr = (void __user *)ctrls->controls;
-			*kernel_ptr = (void *)&ctrls->controls;
+			*kernel_ptr = (void **)&ctrls->controls;
 			*array_size = sizeof(struct v4l2_ext_control)
 				    * ctrls->count;
 			ret = 1;
@@ -2412,7 +2412,7 @@ video_usercopy(struct file *file, unsigned int cmd, unsigned long arg,
 	}
 
 	if (has_array_args) {
-		*kernel_ptr = user_ptr;
+		*kernel_ptr = (void __force *)user_ptr;
 		if (copy_to_user(user_ptr, mbuf, array_size))
 			err = -EFAULT;
 		goto out_array_args;