drivers/rtc/rtc-rs5c372.c: use %*ph to dump small buffers

Instead of pushing each byte let's reduce stack usage by using %*ph specifier.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>