fix wifi build

Author: mykrupp

src/platform/silabs/SiWx917/OTAImageProcessorImpl.cpp

@@ -39,6 +39,7 @@ extern "C" {
 #define SL_BOOTLOADER_OK 0L
 #define SL_STATUS_FW_UPDATE_DONE SL_STATUS_SI91X_NO_AP_FOUND
 uint8_t flag = RPS_HEADER;
+static chip::OTAImageProcessorImpl gImageProcessor;
 
 namespace chip {
 
@@ -49,6 +50,15 @@ uint32_t OTAImageProcessorImpl::mWriteOffset
 uint16_t OTAImageProcessorImpl::writeBufOffset                                          = 0;
 uint8_t OTAImageProcessorImpl::writeBuffer[kAlignmentBytes] __attribute__((aligned(4))) = { 0 };
 
+CHIP_ERROR OTAImageProcessorImpl::Init(OTADownloader * downloader)
+{
+    ReturnErrorCodeIf(downloader == nullptr, CHIP_ERROR_INVALID_ARGUMENT);
+
+    gImageProcessor.SetOTADownloader(downloader);
+
+    return CHIP_NO_ERROR;
+}
+
 CHIP_ERROR OTAImageProcessorImpl::PrepareDownload()
 {
     DeviceLayer::PlatformMgr().ScheduleWork(HandlePrepareDownload, reinterpret_cast<intptr_t>(this));
@@ -355,4 +365,9 @@ CHIP_ERROR OTAImageProcessorImpl::ReleaseBlock()
     return CHIP_NO_ERROR;
 }
 
+OTAImageProcessorImpl & OTAImageProcessorImpl::GetDefaultInstance()
+{
+    return gImageProcessor;
+}
+
 } // namespace chip