Check maximum allowed download size for download command.

Bug: 117272937
Test: fastboot flashall
Change-Id: Ied34a89129813a7f9fce6d4f48d8b65967558731
diff --git a/fastboot/device/commands.cpp b/fastboot/device/commands.cpp
index 3f663ef..042e337 100644
--- a/fastboot/device/commands.cpp
+++ b/fastboot/device/commands.cpp
@@ -165,7 +165,7 @@
     }
     // arg[0] is the command name, arg[1] contains size of data to be downloaded
     unsigned int size;
-    if (!android::base::ParseUint("0x" + args[1], &size, UINT_MAX)) {
+    if (!android::base::ParseUint("0x" + args[1], &size, kMaxDownloadSizeDefault)) {
         return device->WriteStatus(FastbootResult::FAIL, "Invalid size");
     }
     device->download_data().resize(size);