ivi-layout: make sure the rectangle calculated by…

ivi-layout: make sure the rectangle calculated by calc_inverse_matrix_transform() is never too small

It's ok if the rectangle is too large: If the calculation fails, the bounding rectangle is used anyways. However, a rectangle that is too small will create incorrect results. So make sure to round all edges outwards.

Signed-off-by: Michael Olbrich m.olbrich@pengutronix.de