ipmi: use %*ph to print small buffer

Use %*ph format to print small buffer as hex string.

The change is safe since the specifier can handle up to 64 bytes and taking
into account the buffer size of 100 bytes on stack the function has never been
used to dump more than 32 bytes. Note, this also avoids potential buffer
overflow if the length of the input buffer is bigger.

This completely eliminates ipmi_debug_msg() in favour of Dynamic Debug.

Signed-off-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Message-Id: <20191011155036.36748-1-andriy.shevchenko@linux.intel.com>
Signed-off-by: Corey Minyard <cminyard@mvista.com>