nvramtool: Read/write binary data as binary

Only relevant on windows (and nvramtool currently fails there), but
it doesn't hurt.

Change-Id: I5d6420c1f9dc49cf3af31e75088e51a90f729e01
Signed-off-by: Patrick Georgi <patrick.georgi@secunet.com>
Reviewed-on: http://review.coreboot.org/1535
Tested-by: build bot (Jenkins)
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>
diff --git a/util/nvramtool/cli/nvramtool.c b/util/nvramtool/cli/nvramtool.c
index f3fb16d..f283463 100644
--- a/util/nvramtool/cli/nvramtool.c
+++ b/util/nvramtool/cli/nvramtool.c
@@ -402,7 +402,7 @@
 	unsigned char data[CMOS_SIZE];
 	FILE *f;
 
-	if ((f = fopen(nvramtool_op.param, "w")) == NULL) {
+	if ((f = fopen(nvramtool_op.param, "wb")) == NULL) {
 		fprintf(stderr, "%s: Can not open file %s for writing: %s\n",
 			prog_name, nvramtool_op.param, strerror(errno));
 		exit(1);
@@ -434,7 +434,7 @@
 	size_t nr_bytes;
 	FILE *f;
 
-	if ((f = fopen(nvramtool_op.param, "r")) == NULL) {
+	if ((f = fopen(nvramtool_op.param, "rb")) == NULL) {
 		fprintf(stderr, "%s: Can not open file %s for reading: %s\n",
 			prog_name, nvramtool_op.param, strerror(errno));
 		exit(1);