zynq: Increase the early malloc() size

This is needed to support driver-model conversion of USB and block devices.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/arm/mach-zynq/Kconfig b/arch/arm/mach-zynq/Kconfig
index db3c579..a982320 100644
--- a/arch/arm/mach-zynq/Kconfig
+++ b/arch/arm/mach-zynq/Kconfig
@@ -17,4 +17,7 @@
 	  Based on this option include/configs/<CONFIG_SYS_CONFIG_NAME>.h header
 	  will be used for board configuration.
 
+config SYS_MALLOC_F_LEN
+	default 0x600
+
 endif