mfd: arizona: Remove #ifdef guards for PM related functions

Only export the arizona_pm_ops if CONFIG_PM is set, but leave the
suspend/resume functions (and related code) outside #ifdef guards.

If CONFIG_PM is not set, the arizona_pm_ops will be defined as
"static __maybe_unused", and the structure plus all the callbacks will
be automatically dropped by the compiler.

This has the advantage of always compiling these functions in,
independently of any Kconfig option. Thanks to that, bugs and other
regressions are subsequently easier to catch.

Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Acked-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Signed-off-by: Lee Jones <lee@kernel.org>