ARM: at91/dt: sama5d4: fix lcdck clock definition

lcdck takes mck (not smd) as its parent. It is also assigned id 3 and not 4.

Signed-off-by: Boris BREZILLON <boris.brezillon@free-electrons.com>
[nicolas.ferre@atmel.com: squashed 2 related patches]
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>