fix(fed4): remove unused OPI flash mode configurations

Author: strid3r21

boards.txt

@@ -50681,11 +50681,6 @@ fed4.menu.FlashMode.dio.build.flash_mode=dio
 fed4.menu.FlashMode.dio.build.boot=dio
 fed4.menu.FlashMode.dio.build.boot_freq=80m
 fed4.menu.FlashMode.dio.build.flash_freq=80m
-fed4.menu.FlashMode.opi=OPI 80MHz
-fed4.menu.FlashMode.opi.build.flash_mode=dout
-fed4.menu.FlashMode.opi.build.boot=opi
-fed4.menu.FlashMode.opi.build.boot_freq=80m
-fed4.menu.FlashMode.opi.build.flash_freq=80m
 
 fed4.menu.FlashSize.16M=16MB (128Mb)
 fed4.menu.FlashSize.16M.build.flash_size=16MB