Fpga: fix incorrect test of CFG_FPGA_XILINX macro

CFG_FPGA_XILINX is a bit value used to test against the value in
CONFIG_FPGA.  Testing for a value will always return TRUE.  I don't
think that is the intention in this code.

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
diff --git a/common/cmd_fpga.c b/common/cmd_fpga.c
index 3fc4fca..cce23ad 100644
--- a/common/cmd_fpga.c
+++ b/common/cmd_fpga.c
@@ -60,6 +60,7 @@
 /* Convert bitstream data and load into the fpga */
 int fpga_loadbitstream(unsigned long dev, char* fpgadata, size_t size)
 {
+#if (CONFIG_FPGA & CFG_FPGA_XILINX)
 	unsigned int length;
 	unsigned char* swapdata;
 	unsigned int swapsize;
@@ -72,7 +73,6 @@
 
 	dataptr = (unsigned char *)fpgadata;
 
-#if CFG_FPGA_XILINX
 	/* skip the first bytes of the bitsteam, their meaning is unknown */
 	length = (*dataptr << 8) + *(dataptr+1);
 	dataptr+=2;