RMX1921: init: Enable fastchg_fw_update and ui_soc_decimal on boot

 * `fastchg_fw_update` seems to be needed to initialize VOOC / Warp
   charging.
 * `ui_soc_decimal` isn't exactly needed, as it seems to be more for
   enabling the ability to calculate decimal percentages for remaining
   battery capacity on the lockscreen for Oxygen OS. Nevertheless, it
   doesn't seem to cause harm to enable this anyway.

Change-Id: I03dd1abe9c2c7be0b7b7576721b6f6338f1afd46
Signed-off-by: kaderbava <ksbava7325@gmail.com>