ARM: at91/dt: sam9263: Add missing clocks to lcdc node

atmel_lcdfb needs also uses hclk clock, but AT91SAM9263 doesn't have that
specific clock, so use lcd_clk twice. The same was done in
arch/arm/mach-at91/at91sam9263.c

Signed-off-by: Alexander Stein <alexanders83@web.de>
Acked-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>