misc: Mark MICROCODE_MINOR unused

misc: Mark MICROCODE_MINOR unused

This one is unused since

  1461e36e9413 ("x86/microcode: Rip out the OLD_INTERFACE")

so comment it out.

Link: https://lore.kernel.org/r/20220525161232.14924-1-bp@alien8.de
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20220727114948.30123-1-bp@alien8.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>