fpga: Add bitstream type BIT_NONE

Add bitstream type BIT_NONE to the bitstream type
enum. This might be useful while loading bitstreams
in respective drivers.

Signed-off-by: Siva Durga Prasad Paladugu <sivadur@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>

include/fpga.h

@@ -46,6 +46,7 @@ typedef struct {                /* typedef fpga_desc */
 typedef enum {
 	BIT_FULL = 0,
 	BIT_PARTIAL,
+	BIT_NONE = 0xFF,
 } bitstream_type;
 
 /* root function definitions */