pxe: Move common parsing coding into pxe_util

Both the syslinux and pxe commands use essentially the same code to parse
and run extlinux.conf files. Move this into a common function.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Artem Lapkin <email2tema@gmail.com>
Tested-by: Artem Lapkin <email2tema@gmail.com>
Reviewed-by: Ramon Fried <rfried.dev@gmail.com>
diff --git a/boot/pxe_utils.c b/boot/pxe_utils.c
index 6ecd15c..f40ad2b 100644
--- a/boot/pxe_utils.c
+++ b/boot/pxe_utils.c
@@ -1505,3 +1505,23 @@
 	ctx->userdata = userdata;
 	ctx->allow_abs_path = allow_abs_path;
 }
+
+int pxe_process(struct pxe_context *ctx, ulong pxefile_addr_r, bool prompt)
+{
+	struct pxe_menu *cfg;
+
+	cfg = parse_pxefile(ctx, pxefile_addr_r);
+	if (!cfg) {
+		printf("Error parsing config file\n");
+		return 1;
+	}
+
+	if (prompt)
+		cfg->prompt = 1;
+
+	handle_pxe_menu(ctx, cfg);
+
+	destroy_pxe_menu(cfg);
+
+	return 0;
+}