davinci_vpfe: workaround a bug with allocated DMA pages

Let the driver use 4 instead of 3 predefined DMA buffers. This circumvents the calling of broken buffer_setup/buffer_release functions.

include/media/davinci_vpfe.h

@@ -89,7 +89,7 @@
 /* 4:2:2 data */
 #define VPFE_MAX_FBUF_SIZE       (VPFE_MAX_FRAME_WIDTH*VPFE_MAX_FRAME_HEIGHT*2)
 /* frame buffers allocate at driver initialization time */
-#define VPFE_DEFNUM_FBUFS             3
+#define VPFE_DEFNUM_FBUFS             4
 
 #define VPFE_MAX_FBUF_ORDER \
    get_order(roundup_pow_of_two(VPFE_MAX_FBUF_SIZE))