i2c: sun6i_p2wi: Initialize chips in .child_pre_probe

i2c: sun6i_p2wi: Initialize chips in .child_pre_probe

Chips attached to the P2WI bus require an initialization command before
they can be used. (Specifically, this switches the chip from I2C mode
to P2WI mode.) The driver does this in its .probe_chip hook, under the
assumption that .probe_chip is called during child probe. This is not
the case; .probe_chip is only called by dm_i2c_probe, which is intended
for use by board-level code, not for chips with OF nodes.

Since this initialization command must be run before a child chip can be
used, do it before probing each child.

Signed-off-by: Samuel Holland <samuel@sholland.org>
Acked-by: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: Andre Przywara <andre.przywara@arm.com>