microblaze: Copy bootfile from variables

Setup bootfile.

Signed-off-by: Michal Simek <monstr@monstr.eu>
diff --git a/arch/microblaze/lib/board.c b/arch/microblaze/lib/board.c
index d677329..ca5882d 100644
--- a/arch/microblaze/lib/board.c
+++ b/arch/microblaze/lib/board.c
@@ -186,6 +186,10 @@
 	uchar enetaddr[6];
 	eth_getenv_enetaddr("ethaddr", enetaddr);
 	printf("MAC:   %pM\n", enetaddr);
+
+	s = getenv("bootfile");
+	if (s != NULL)
+		copy_filename(BootFile, s, sizeof(BootFile));
 #endif
 
 	/* main_loop */