extcon: palmas: remove assigning "edev.name" to palmas

of_extcon_get_extcon_dev() uses dev_name for getting the reference
to the extcon device. If the extcon driver assigns a different
name other than dev_name, of_extcon_get_extcon_dev() wouldn't
be able to find the reference to the extcon device. Since the
client drivers of extcon-palmas would be using
of_extcon_get_extcon_dev(), removed assigning edev.name
in extcon-palmas.

Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: Myungjoo Ham <myungjoo.ham@samsung.com>