arm: mx6: novena: Define CONFIG_SYS_MALLOC_F_LEN

This board uses setup_i2c() in SPL. The setup_i2c() function internally
calls gpio_request(), which in turn internally calls strdup(). The strdup()
requires a running mallocator, so this patch makes the mallocator available.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Igor Grinberg <grinberg@compulab.co.il>
Cc: Nikita Kiryanov <nikita@compulab.co.il>
Cc: Sean Cross <xobs@kosagi.com>
Cc: Simon Glass <sjg@chromium.org>
Cc: Stefano Babic <sbabic@denx.de>
Cc: Tim Harvey <tharvey@gateworks.com>
diff --git a/include/configs/novena.h b/include/configs/novena.h
index 879141a..0f3621a 100644
--- a/include/configs/novena.h
+++ b/include/configs/novena.h
@@ -115,6 +115,7 @@
 #define CONFIG_SYS_MEMTEST_END		0x20000000
 
 #define CONFIG_SYS_MALLOC_LEN		(64 * 1024 * 1024)
+#define CONFIG_SYS_MALLOC_F_LEN		(1 << 10)
 
 /* SPL */
 #define CONFIG_SPL_FAT_SUPPORT