fpga: Export fpga_get_desc for SPL

SPL needs to detect FPGA device which will be used
for loading bitstream.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
diff --git a/include/fpga.h b/include/fpga.h
index ef044e9..e0d1298 100644
--- a/include/fpga.h
+++ b/include/fpga.h
@@ -52,6 +52,7 @@
 void fpga_init(void);
 int fpga_add(fpga_type devtype, void *desc);
 int fpga_count(void);
+const fpga_desc *const fpga_get_desc(int devnum);
 int fpga_load(int devnum, const void *buf, size_t bsize,
 	      bitstream_type bstype);
 int fpga_fsload(int devnum, const void *buf, size_t size,