mfd: Represent correct filenames in file headers

The original author(s) probably copy/pasted these headers from the
existing public header files.

Signed-off-by: Laszlo Papp <lpapp@kde.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

diff --cc include/linux/mfd/max77686-private.h
Simple merge

diff --cc include/linux/mfd/max8997-private.h
Simple merge

diff --cc include/linux/mfd/max8998-private.h
Simple merge