[batterytracker] Fix logging format strings. JB#41302
[batterytracker] Fix logging format strings. JB#41302

Loop counter was changed from int to size_t type, but format strings
were not updated accordingly - which makes aarch64 builds fail.

Update format string to match passed arguments.

Signed-off-by: Simo Piiroinen <6d5e5360bed3d486f7d9fb26b0f737f7d4fd45ee@jollamobile.com>

spiiroin/dsme,spiiroin/dsme