HID: i2c-hid: use uniform debugging APIs

Only two locations in i2c-hid are using the standard dev_dbg() APIs.
The rest are all using the custom i2c_hid_dbg(), which in turn uses
dev_dbg().

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>