Fix OMV4 build.
#define OMV_FB_SIZE (400K) // FB memory: header + VGA/GS image
#define OMV_FB_ALLOC_SIZE (100K) // minimum fb alloc size
-#define OMV_STACK_SIZE (8K)
+#define OMV_STACK_SIZE (7K)
#define OMV_HEAP_SIZE (240K)
#define OMV_LINE_BUF_SIZE (3K) // Image line buffer round(640 * 2BPP * 2 buffers).
