The driver has problems with the different components of
the charging code racing with each other to probe().

This results in all four subdrivers populating battery
information to ascertain that it is populated for their
own needs for example.

Fix this by using component probing and thus expressing
to the kernel that these are dependent components.
The probes can happen in any order and will only acquire
resources such as state container, regulators and
interrupts and initialize the data structures, but no
execution happens until the .bind() callback is called.

The charging driver is the main component and binds
first, then bind in order the three subcomponents:
ab8500-fg, ab8500-btemp and ab8500-chargalg.

Do some housekeeping while we are moving the code around.
Like use devm_* for IRQs so as to cut down on some
boilerplate.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>