tps65090-charger: Use "IS_ENABLED(CONFIG_OF)" for DT code

Instead of "#if defined(CONFIG_OF)" use "IS_ENABLED(CONFIG_OF)" option
for DT code to avoid if-deffery in code.

Also, arranged header files in alphabetically.

Signed-off-by: Manish Badarkhe <badarkhe.manish@gmail.com>
Acked-by: Rhyland Klein <rklein@nvidia.com>
Signed-off-by: Anton Vorontsov <anton@enomsg.org>