boundary->width and boundary->height are sizes relative to
boundary->left and boundary->top coordinates, but they were not being
taken into consideration to adjust r->left and r->top, leading to the
following error:

Consider the follow as initial values for boundary and r:

struct v4l2_rect boundary = {
	.left = 100,
	.top = 100,
	.width = 800,
	.height = 600,
}

struct v4l2_rect r = {
	.left = 0,
	.top = 0,
	.width = 1920,
	.height = 960,
}

calling v4l2_rect_map_inside(&r, &boundary) was modifying r to:

r = {
	.left = 0,
	.top = 0,
	.width = 800,
	.height = 600,
}

Which is wrongly outside the boundary rectangle, because:

	v4l2_rect_set_max_size(r, boundary); // r->width = 800, r->height = 600
	...
	if (r->left + r->width > boundary->width) // true
		r->left = boundary->width - r->width; // r->left = 800 - 800
	if (r->top + r->height > boundary->height) // true
		r->top = boundary->height - r->height; // r->height = 600 - 600

Fix this by considering top/left coordinates from boundary.

Fixes: ac49de8c ("[media] v4l2-rect.h: new header with struct v4l2_rect helper functions")
Signed-off-by: Helen Koike <helen.koike@collabora.com>
Cc: <stable@vger.kernel.org>      # for v4.7 and up
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>