drivers/rtc/rtc-puv3.c: use dev_dbg() instead of dev_debug() for typo issue

It is only a typo issue, the related commit:

  "1fbc4c4d

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

The related error (unicore32 with allmodconfig):

    CC [M]  drivers/rtc/rtc-puv3.o
  drivers/rtc/rtc-puv3.c: In function 'puv3_rtc_setpie':
  drivers/rtc/rtc-puv3.c:74: error: implicit declaration of function 'dev_debug'

Signed-off-by: Chen Gang <gang.chen.5i5j@gmail.com>
Acked-by: Xuetao Guan <gxt@mprc.pku.edu.cn>
Signed-off-by: Xuetao Guan <gxt@mprc.pku.edu.cn>