ARM: qemu-arm: Increase CONFIG_SYS_CBSIZE

CONFIG_SYS_CBSIZE determines the maximum length of the kernel command
line, and the default value of 256 is too small for booting some Linux
images in the wild.

Signed-off-by: Tuomas Tynkkynen <tuomas.tynkkynen@iki.fi>
diff --git a/include/configs/qemu-arm.h b/include/configs/qemu-arm.h
index c968aa7..839bc10 100644
--- a/include/configs/qemu-arm.h
+++ b/include/configs/qemu-arm.h
@@ -47,4 +47,6 @@
 	"ramdisk_addr_r=0x44000000\0" \
 	BOOTENV
 
+#define CONFIG_SYS_CBSIZE 512
+
 #endif /* __CONFIG_H */