drivers/rtc/rtc-puv3.c: use dev_dbg() instead of pr_debug()

Because dev_*() are used along with pr_debug() function in this code, the
debug message is not tidy.  This patch converts from pr_debug() to
dev_dbg() since dev_*() are encouraged to use in device driver code.

Signed-off-by: Sangjung Woo <sangjung.woo@samsung.com>
Cc: Guan Xuetao <gxt@mprc.pku.edu.cn>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>