z2: Make providing flash images non-mandatory

Up to now, the z2 machine only boots if a flash image is 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: NGuenter Roeck <linux@roeck-us.net>
Reviewed-by: NPhilippe Mathieu-Daudé <philmd@redhat.com>
Message-id: 20200217210903.18602-1-linux@roeck-us.net
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

hw/arm/z2.c

@@ -314,12 +314,6 @@ static void z2_init(MachineState *machine)
     be = 0;
 #endif
     dinfo = drive_get(IF_PFLASH, 0, 0);
-    if (!dinfo && !qtest_enabled()) {
-        error_report("Flash image must be given with the "
-                     "'pflash' parameter");
-        exit(1);
-    }
-
     if (!pflash_cfi01_register(Z2_FLASH_BASE, "z2.flash0", Z2_FLASH_SIZE,
                                dinfo ? blk_by_legacy_dinfo(dinfo) : NULL,
                                sector_len, 4, 0, 0, 0, 0, be)) {