mxser: clean up the rest of MUST helpers

Clean up the rest of MUST helpers. They all can use the newly added
mxser_must_set_EFR. And passing a bool instead of having two functions
(_enable+_disable) simplifies the code a lot too.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20210618061516.662-43-jslaby@suse.cz


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>