video: remove support for non-existing atmel,at32ap-lcdc in atmel_lcdfb

The AVR32 architecture has been removed from the kernel in commit
26202873, hence clean out the
atmel,at32ap-lcdc parts in the atmel_lcdfb.c video driver.

AVR32 architecture never supported device tree, hence this code was not
used by anybody.
Signed-off-by: Hans-Christian Noren Egtvedt <egtvedt@samfundet.no>

Documentation/devicetree/bindings/display/atmel,lcdc.txt

@@ -9,7 +9,6 @@ Required properties:
 	"atmel,at91sam9g45-lcdc" ,
 	"atmel,at91sam9g45es-lcdc" ,
 	"atmel,at91sam9rl-lcdc" ,
-	"atmel,at32ap-lcdc"
 - reg : Should contain 1 register ranges(address and length).
 	Can contain an additional register range(address and length)
 	for fixed framebuffer memory. Useful for dedicated memories.