Enable -Wconversion in openiotsdk platform code. (#25410)

Author: bzbarsky-apple

src/platform/openiotsdk/BUILD.gn

@@ -95,4 +95,6 @@ static_library("openiotsdk") {
       "KVBlockDeviceStore.h",
     ]
   }
+
+  cflags = [ "-Wconversion" ]
 }

src/platform/openiotsdk/KVBlockDeviceStore.cpp

@@ -457,7 +457,7 @@ KVBlockDeviceStoreKeyBuilder::KVBlockDeviceStoreKeyBuilder(const char * key)
         if (illegal_ptr)
         {
             *out++ = '!';
-            *out++ = 'A' + (int) (illegal_ptr - illegalCharacters);
+            *out++ = static_cast<char>('A' + (int) (illegal_ptr - illegalCharacters));
         }
         else
         {

src/platform/openiotsdk/KVPsaPsStore.cpp

@@ -601,7 +601,7 @@ void KVPsaPsStoreKeyBuilder::AddKey()
         return;
     }
 
-    uint32_t keyIndex = CONVERT_KEY_TO_INDEX(keyValue);
+    auto keyIndex = CONVERT_KEY_TO_INDEX(keyValue);
     memset(mKvsStoredKeyString[keyIndex], 0, sizeof(mKvsStoredKeyString[keyIndex]));
     Platform::CopyString(mKvsStoredKeyString[keyIndex], buffer);
     KVPsaPsStore::ScheduleKVSKeyMapUpdate();
@@ -614,7 +614,7 @@ void KVPsaPsStoreKeyBuilder::RemoveKey()
         return;
     }
 
-    uint32_t keyIndex = CONVERT_KEY_TO_INDEX(keyValue);
+    auto keyIndex = CONVERT_KEY_TO_INDEX(keyValue);
     memset(mKvsStoredKeyString[keyIndex], 0, sizeof(mKvsStoredKeyString[keyIndex]));
     KVPsaPsStore::ScheduleKVSKeyMapUpdate();
 }

src/platform/openiotsdk/NetworkCommissioningEthernetDriver.cpp

@@ -41,7 +41,7 @@ NetworkIterator * OpenIoTSDKEthernetDriver::GetNetworks()
     char buf[NETIF_NAMESIZE];
     char * ifname = netif_index_to_name(0, buf);
 
-    ret->interfaceNameLen = strlen(ifname);
+    ret->interfaceNameLen = static_cast<uint8_t>(strlen(ifname));
     memcpy(ret->interfaceName, ifname, ret->interfaceNameLen);
 
     return ret;