pcmcia: limit pxa2xx_balloon3 subdriver to balloon3 platform

pxa2xx_balloon3 tries to register pxa2xx-pcmcia device not checking whether
machine is really balloon3, thus messing multi-machine kernels. Fix it up.
Signed-off-by: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
Signed-off-by: Eric Miao <eric.y.miao@gmail.com>

drivers/pcmcia/pxa2xx_balloon3.c

@@ -25,6 +25,8 @@
 
 #include <mach/balloon3.h>
 
+#include <asm/mach-types.h>
+
 #include "soc_common.h"
 
 /*
@@ -127,6 +129,9 @@ static int __init balloon3_pcmcia_init(void)
 {
 	int ret;
 
+	if (!machine_is_balloon3())
+		return -ENODEV;
+
 	balloon3_pcmcia_device = platform_device_alloc("pxa2xx-pcmcia", -1);
 	if (!balloon3_pcmcia_device)
 		return -ENOMEM;