tps6105 driver provides two cells. One is for GPIO and another one is
for selected mode depending on platform data. When tps6105x is used in
GPIO-only mode, this driver calls mfd_add_devices() with mfd_cell
.name == NULL. This value causes an oops in platform_device_register()
later.

The following patch adds a mfd_cell for each possible mode thereby
excluding .name assignment in runtime.
Signed-off-by: Denis Grigoryev <grigoryev@fastwel.ru>
Signed-off-by: Lee Jones <lee.jones@linaro.org>