Ameba Build Issue (#13498)

When moving the files from examples/thermostat/ameba/main to top level of project. GLOBAL_CFLAGS += -DCHIP_PROJECT=1  must be included in the make file.  make all would fail with CHIP_PROJECT=1 becuase the type def's for u32, and u64 were removed
But when u32 is undefined during the chip_main build connectedhomeip/src/lib/core/CHIPTLVReader.cpp will fail since u32 is used a a variable name.

src/lib/core/CHIPTLVReader.cpp

@@ -245,8 +245,8 @@ namespace {
 float BitCastToFloat(const uint64_t elemLenOrVal)
 {
     float f;
-    auto u32 = static_cast<uint32_t>(elemLenOrVal);
-    memcpy(&f, &u32, sizeof(f));
+    auto unsigned32 = static_cast<uint32_t>(elemLenOrVal);
+    memcpy(&f, &unsigned32, sizeof(f));
     return f;
 }
 } // namespace