Adding build.mcu to save name killed export. reverting. fixes #5174 (#5177)

Author: lbernstone

Diff for: platform.txt

@@ -148,8 +148,8 @@ recipe.objcopy.bin.pattern="{tools.esptool_py.path}/{tools.esptool_py.cmd}" {rec
 recipe.objcopy.bin.pattern.linux=python "{tools.esptool_py.path}/{tools.esptool_py.cmd}" {recipe.objcopy.bin.pattern_args}
 
 ## Save bin
-recipe.output.tmp_file={build.project_name}.{build.mcu}.bin
-recipe.output.save_file={build.project_name}.{build.mcu}.{build.variant}.bin
+recipe.output.tmp_file={build.project_name}.bin
+recipe.output.save_file={build.project_name}.{build.variant}.bin
 
 ## Compute size
 recipe.size.pattern="{compiler.path}{compiler.size.cmd}" -A "{build.path}/{build.project_name}.elf"