rtc: rv3028: fix RV3028_TS_COUNT type

Read RV3028_TS_COUNT in an unsigned int so static checkers stop reporting a
mismatch between the format specifier and the type.

Reported-by: Zhu Jun <zhujun2@cmss.chinamobile.com>
Link: https://lore.kernel.org/r/20241111104711.3170865-1-alexandre.belloni@bootlin.com


Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>