ibasso: Use correct API to query power input and charging state
Instead of using the generic hosted sysfs code, which expects
a full path, the ibasso code's sysfs code uses an enumeration.
Unfortunatley the generic power input/charging code used the former
API but linked with the latter. oops.
Correct this by placing a private copy of these functions in
the ibasso-specific port, and removing the generic version from
that build.
(A "proper" fix would be to rework all 17 of the ibasso sysfs calls
to use the generic sysfs API)
Change-Id: Ic13adc9782d85560f0c74d77f60a629619d38668