ANDROID: extcon: fix allocation for edev->bnh

Since the device_register() call was moved later in the function by the
upstream commit cb81ea99 ("extcon: Modify extcon device to be
created after driver data is set"), we need to update the edev->bnh
allocation from devm_kzalloc -> kzalloc. Also, add the kfree for this
allocation accordingly.

Fixes: cb81ea99 ("extcon: Modify extcon device to be created after driver data is set")
Signed-off-by: Will McVicker <willmcvicker@google.com>
Change-Id: Ie997bbe31c84c7acc779043d7f91cfa798082c9f