typo fixed

Firmware/ultralcd.cpp

@@ -4970,7 +4970,7 @@ static bool check_file(const char* filename) {
 	uint32_t filesize;
 	card.openFile(filename, true);
 	filesize = card.getFileSize();
-	if (fileSize > END_FILE_SECTION) {
+	if (filesize > END_FILE_SECTION) {
 		card.setIndex(filesize - END_FILE_SECTION);
 	}