[ARM] pxa/cm-x300: fix ffuart registration

ffuart is available on cm-x300 only with pxa300.

Signed-off-by: Igor Grinberg <grinberg@compulab.co.il>
Cc: stable <stable@kernel.org>
Signed-off-by: Eric Miao <eric.y.miao@gmail.com>
diff --git a/arch/arm/mach-pxa/cm-x300.c b/arch/arm/mach-pxa/cm-x300.c
index 8d227b4..c70e6c2 100644
--- a/arch/arm/mach-pxa/cm-x300.c
+++ b/arch/arm/mach-pxa/cm-x300.c
@@ -746,9 +746,10 @@
 {
 	cm_x300_init_mfp();
 
-	pxa_set_ffuart_info(NULL);
 	pxa_set_btuart_info(NULL);
 	pxa_set_stuart_info(NULL);
+	if (cpu_is_pxa300())
+		pxa_set_ffuart_info(NULL);
 
 	cm_x300_init_da9030();
 	cm_x300_init_dm9000();