mainstone: Make providing flash images non-mandatory

Up to now, the mainstone machine only boots if two flash images are
provided. This is not really necessary; the machine can boot from initrd
or from SD without it. At the same time, having to provide dummy flash
images is a nuisance and does not add any real value. Make it optional.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-id: 20200217210824.18513-1-linux@roeck-us.net
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

hw/arm/mainstone.c

@@ -138,19 +138,10 @@ static void mainstone_common_init(MemoryRegion *address_space_mem,
     /* There are two 32MiB flash devices on the board */
     for (i = 0; i < 2; i ++) {
         dinfo = drive_get(IF_PFLASH, 0, i);
-        if (!dinfo) {
-            if (qtest_enabled()) {
-                break;
-            }
-            error_report("Two flash images must be given with the "
-                         "'pflash' parameter");
-            exit(1);
-        }
-
         if (!pflash_cfi01_register(mainstone_flash_base[i],
                                    i ? "mainstone.flash1" : "mainstone.flash0",
                                    MAINSTONE_FLASH,
-                                   blk_by_legacy_dinfo(dinfo),
+                                   dinfo ? blk_by_legacy_dinfo(dinfo) : NULL,
                                    sector_len, 4, 0, 0, 0, 0, be)) {
             error_report("Error registering flash memory");
             exit(1);