ivi-layout: simplify API
Use assert() to check for invalid NULL arguments. Something like that happens during development and assert() makes it easier to find the error. And it avoids unnecessary additional error handling. The hmi-controller asserts anyways so this just moves the assert on level deeper. Other controller probably do the same thing, or don't check the return values at all.
Signed-off-by: Michael Olbrich m.olbrich@pengutronix.de