fpga: Add support for gzip images with bitstreams

Here is the set of command which has been performed
to proof this feature.

gzip < fpga.bin > fpga.bin.gz
mkimage -A arm -O u-boot -T firmware -C gzip \
-a 20000000 -n "zc702_fpga_bin" -d fpga.bin.gz fpga.bin.gz.ub

tftp 100000 fpga.bin.gz.ub
fpga loadmk 0 100000

This flow should speedup loading bitstream data
from external memory and save image footprint in non volatile
memory.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Acked-by: Jagannadha Sutradharudu Teki <jaganna@xilinx.com>

common/cmd_fpga.c

@@ -160,9 +160,25 @@ int do_fpga(cmd_tbl_t *cmdtp, int flag, int argc, char *const argv[])
 				image_header_t *hdr =
 						(image_header_t *)fpga_data;
 				ulong data;
-
-				data = (ulong)image_get_data(hdr);
-				data_size = image_get_data_size(hdr);
+				uint8_t comp;
+
+				comp = image_get_comp(hdr);
+				if (comp == IH_COMP_GZIP) {
+					ulong image_buf = image_get_data(hdr);
+					data = image_get_load(hdr);
+					ulong image_size = ~0UL;
+
+					if (gunzip((void *)data, ~0UL,
+						   (void *)image_buf,
+						   &image_size) != 0) {
+						puts("GUNZIP: error\n");
+						return 1;
+					}
+					data_size = image_size;
+				} else {
+					data = (ulong)image_get_data(hdr);
+					data_size = image_get_data_size(hdr);
+				}
 				rc = fpga_load(dev, (void *)data, data_size);
 			}
 			break;