rtc: bq32k: use sysfs_emit() instead of sprintf()

Use sysfs_emit() instead of sprintf() in the sysfs show callback
(bq32k_sysfs_show_tricklecharge_bypass) to conform to the recommended
sysfs attribute formatting guidelines in
Documentation/filesystems/sysfs.rst.

Link: https://patch.msgid.link/20261029132339.925021-4-alexandre.belloni@bootlin.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>