hw/i386/multiboot.c: Don't use load_image()

The load_image() function is deprecated, as it does not let the
caller specify how large the buffer to read the file into is.
Instead use load_image_size().

While we are converting the code, add the missing error check.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-id: 20181130151712.2312-7-peter.maydell@linaro.org

hw/i386/multiboot.c

@@ -343,7 +343,11 @@ int load_multiboot(FWCfgState *fw_cfg,
             mbs.mb_buf_size = TARGET_PAGE_ALIGN(mb_mod_length + mbs.mb_buf_size);
             mbs.mb_buf = g_realloc(mbs.mb_buf, mbs.mb_buf_size);
 
-            load_image(one_file, (unsigned char *)mbs.mb_buf + offs);
+            if (load_image_size(one_file, (unsigned char *)mbs.mb_buf + offs,
+                                mbs.mb_buf_size - offs) < 0) {
+                error_report("Error loading file '%s'", one_file);
+                exit(1);
+            }
             mb_add_mod(&mbs, mbs.mb_buf_phys + offs,
                        mbs.mb_buf_phys + offs + mb_mod_length, c);