atmel_lcdfb: adjust fifo size for at91sam9rl

AT91SAM9RL soc has a 2048 bytes deep FIFO, like AT91SAM9263.

[bn@niasdigital.com: fix build breakage in atmel_lcdfb]
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Cc: Nicolas FERRE <nicolas.ferre@rfo.atmel.com>
Cc: Andrew Victor <andrew@sanpeople.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>