roms: allow roms to be loaded at address 0

It was possible to load roms at address 0, but commit
632cf034b401cdd01dae253a8b577fe518e37654 started to forbid that, which
broke at least ARM versatile.

Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>

hw/loader.c

@@ -636,8 +636,6 @@ static void rom_reset(void *unused)
     Rom *rom;
 
     QTAILQ_FOREACH(rom, &roms, next) {
-        if (rom->addr == 0)
-            continue;
         if (rom->data == NULL)
             continue;
         cpu_physical_memory_write_rom(rom->addr, rom->data, rom->romsize);
@@ -656,8 +654,6 @@ int rom_load_all(void)
     Rom *rom;
 
     QTAILQ_FOREACH(rom, &roms, next) {
-        if (rom->addr == 0)
-            continue;
         if (addr > rom->addr) {
             fprintf(stderr, "rom: requested regions overlap "
                     "(rom %s. free=0x" TARGET_FMT_plx
@@ -693,8 +689,6 @@ static Rom *find_rom(target_phys_addr_t addr)
     Rom *rom;
 
     QTAILQ_FOREACH(rom, &roms, next) {
-        if (rom->addr == 0)
-            continue;
         if (rom->addr > addr)
             continue;
         if (rom->addr + rom->romsize < addr)
@@ -712,8 +706,6 @@ int rom_copy(uint8_t *dest, target_phys_addr_t addr, size_t size)
     Rom *rom;
 
     QTAILQ_FOREACH(rom, &roms, next) {
-        if (rom->addr == 0)
-            continue;
         if (rom->addr > addr)
             continue;
         if (rom->addr + rom->romsize < addr)