pda_power: Remove ac_draw_failed goto and label

A previous patch added the ac_draw_failed goto and label to
pda_power_probe(). The goto would be invoked after a failed call to
regulator_get().

However the way ac_draw is used - always after a check for NULL - suggests
that a failed call to regulator_get() was not fatal.

This patch removes the ac_draw_failed goto and label, partly reverting the
previous patch.

This patch also removes the assignment of an error code to ret after a
failed call to regulator_get(), since the error code is now never used.

Signed-off-by: Paul Parsons <lost.distance@yahoo.com>
Cc: Philipp Zabel <philipp.zabel@gmail.com>
Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org>