milkymist: Check for failure trying to load BIOS image

Check the return value from load_image_targphys(), which tells us
whether our attempt to load the BIOS image into RAM failed.
(Spotted by Coverity, CID 1190305.)

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Acked-by: Michael Walle <michael@walle.cc>
Message-id: 20181030170032.1844-1-peter.maydell@linaro.org
diff --git a/hw/lm32/milkymist.c b/hw/lm32/milkymist.c
index 321f184..63c6894 100644
--- a/hw/lm32/milkymist.c
+++ b/hw/lm32/milkymist.c
@@ -138,7 +138,10 @@
     bios_filename = qemu_find_file(QEMU_FILE_TYPE_BIOS, bios_name);
 
     if (bios_filename) {
-        load_image_targphys(bios_filename, BIOS_OFFSET, BIOS_SIZE);
+        if (load_image_targphys(bios_filename, BIOS_OFFSET, BIOS_SIZE) < 0) {
+            error_report("could not load bios '%s'", bios_filename);
+            exit(1);
+        }
     }
 
     reset_info->bootstrap_pc = BIOS_OFFSET;